CVE-2026-52945 (GCVE-0-2026-52945)

Vulnerability from cvelistv5 – Published: 2026-06-24 16:26 – Updated: 2026-10-19 19:47
VLAI
Title
Revert "wireguard: device: enable threaded NAPI"
Summary
In the Linux kernel, the following vulnerability has been resolved: Revert "wireguard: device: enable threaded NAPI" This reverts commit 933466fc50a8e4eb167acbd0d8ec96a078462e9c which is commit db9ae3b6b43c79b1ba87eea849fd65efa05b4b2e upstream. We have had three independent production user reports in combination with Cilium utilizing WireGuard as encryption underneath that k8s Pod E/W traffic to certain peer nodes fully stalled. The situation appears as follows: - Occurs very rarely but at random times under heavy networking load. - Once the issue triggers the decryption side stops working completely for that WireGuard peer, other peers keep working fine. The stall happens also for newly initiated connections towards that particular WireGuard peer. - Only the decryption side is affected, never the encryption side. - Once it triggers, it never recovers and remains in this state, the CPU/mem on that node looks normal, no leak, busy loop or crash. - bpftrace on the affected system shows that wg_prev_queue_enqueue fails, thus the MAX_QUEUED_PACKETS (1024 skbs!) for the peer's rx_queue is reached. - Also, bpftrace shows that wg_packet_rx_poll for that peer is never called again after reaching this state for that peer. For other peers wg_packet_rx_poll does get called normally. - Commit db9ae3b ("wireguard: device: enable threaded NAPI") switched WireGuard to threaded NAPI by default. The default has not been changed for triggering the issue, neither did CPU hotplugging occur (i.e. 5bd8de2 ("wireguard: queueing: always return valid online CPU in wg_cpumask_choose_online()")). - The issue has been observed with stable kernels of v5.15 as well as v6.1. It was reported to us that v5.10 stable is working fine, and no report on v6.6 stable either (somewhat related discussion in [0] though). - In the WireGuard driver the only material difference between v5.10 stable and v5.15 stable is the switch to threaded NAPI by default. [0] https://lore.kernel.org/netdev/CA+wXwBTT74RErDGAnj98PqS=wvdh8eM1pi4q6tTdExtjnokKqA@mail.gmail.com/ Breakdown of the problem: 1) skbs arriving for decryption are enqueued to the peer->rx_queue in wg_packet_consume_data via wg_queue_enqueue_per_device_and_peer. 2) The latter only moves the skb into the MPSC peer queue if it does not surpass MAX_QUEUED_PACKETS (1024) which is kept track in an atomic counter via wg_prev_queue_enqueue. 3) In case enqueueing was successful, the skb is also queued up in the device queue, round-robin picks a next online CPU, and schedules the decryption worker. 4) The wg_packet_decrypt_worker, once scheduled, picks these up from the queue, decrypts the packets and once done calls into wg_queue_enqueue_per_peer_rx. 5) The latter updates the state to PACKET_STATE_CRYPTED on success and calls napi_schedule on the per peer->napi instance. 6) NAPI then polls via wg_packet_rx_poll. wg_prev_queue_peek checks on the peer->rx_queue. It will wg_prev_queue_dequeue if the queue->peeked skb was not cached yet, or just return the latter otherwise. (wg_prev_queue_drop_peeked later clears the cache.) 7) From an ordering perspective, the peer->rx_queue has skbs in order while the device queue with the per-CPU worker threads from a global ordering PoV can finish the decryption and signal the skb PACKET_STATE_CRYPTED out of order. 8) A situation can be observed that the first packet coming in will be stuck waiting for the decryption worker to be scheduled for a longer time when the system is under pressure. 9) While this is the case, the other CPUs in the meantime finish decryption and call into napi_schedule. 10) Now in wg_packet_rx_poll it picks up the first in-order skb from the peer->rx_queue and sees that its state is still PACKET_STATE_UNCRYPTED. The NAPI poll routine then exits e ---truncated---
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 15:23 UTC
CWE
  • CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6641 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 18e65229a328304a7ef59899a30fd34ad73ed56b , < cfdb22762f903d95c36ab91e9fe6167f22fa9f6d (git)
Affected: fb978675ccfd4a93549e49624127d8332cc61cbf , < 42bc3f45425b607a5ca7b7aaaab661b54407c8f8 (git)
Affected: 8c9e9cd398777fd60ba202211da1110614cb5bc5 , < 168ee1549fa24fff2ab924a2ca7b1d85f30e062d (git)
Affected: 933466fc50a8e4eb167acbd0d8ec96a078462e9c , < e94b369ff82f9bc84f090f271bd78f41c9f6ab2f (git)
Affected: aba544ff9ec522e120b1b3d8b32efa4e6d16d4d7 (git)
Affected: 6.15.3 , < 6.16 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 5.15.186 , < 5.15.201 (semver)
Affected: 6.1.142 , < 6.1.164 (semver)
Affected: 6.6.94 , < 6.6.127 (semver)
Affected: 6.12.34 , < 6.12.74 (semver)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-52945",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-16T15:23:09.444431Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-362",
                "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-19T19:47:08.895Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireguard/device.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cfdb22762f903d95c36ab91e9fe6167f22fa9f6d",
              "status": "affected",
              "version": "18e65229a328304a7ef59899a30fd34ad73ed56b",
              "versionType": "git"
            },
            {
              "lessThan": "42bc3f45425b607a5ca7b7aaaab661b54407c8f8",
              "status": "affected",
              "version": "fb978675ccfd4a93549e49624127d8332cc61cbf",
              "versionType": "git"
            },
            {
              "lessThan": "168ee1549fa24fff2ab924a2ca7b1d85f30e062d",
              "status": "affected",
              "version": "8c9e9cd398777fd60ba202211da1110614cb5bc5",
              "versionType": "git"
            },
            {
              "lessThan": "e94b369ff82f9bc84f090f271bd78f41c9f6ab2f",
              "status": "affected",
              "version": "933466fc50a8e4eb167acbd0d8ec96a078462e9c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "aba544ff9ec522e120b1b3d8b32efa4e6d16d4d7",
              "versionType": "git"
            },
            {
              "lessThan": "6.16",
              "status": "affected",
              "version": "6.15.3",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireguard/device.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5.15.201",
              "status": "affected",
              "version": "5.15.186",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.164",
              "status": "affected",
              "version": "6.1.142",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.127",
              "status": "affected",
              "version": "6.6.94",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.74",
              "status": "affected",
              "version": "6.12.34",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.201",
                  "versionStartIncluding": "5.15.186",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.164",
                  "versionStartIncluding": "6.1.142",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.127",
                  "versionStartIncluding": "6.6.94",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.74",
                  "versionStartIncluding": "6.12.34",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.15.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"wireguard: device: enable threaded NAPI\"\n\nThis reverts commit 933466fc50a8e4eb167acbd0d8ec96a078462e9c which is\ncommit db9ae3b6b43c79b1ba87eea849fd65efa05b4b2e upstream.\n\nWe have had three independent production user reports in combination\nwith Cilium utilizing WireGuard as encryption underneath that k8s Pod\nE/W traffic to certain peer nodes fully stalled. The situation appears\nas follows:\n\n  - Occurs very rarely but at random times under heavy networking load.\n  - Once the issue triggers the decryption side stops working completely\n    for that WireGuard peer, other peers keep working fine. The stall\n    happens also for newly initiated connections towards that particular\n    WireGuard peer.\n  - Only the decryption side is affected, never the encryption side.\n  - Once it triggers, it never recovers and remains in this state,\n    the CPU/mem on that node looks normal, no leak, busy loop or crash.\n  - bpftrace on the affected system shows that wg_prev_queue_enqueue\n    fails, thus the MAX_QUEUED_PACKETS (1024 skbs!) for the peer\u0027s\n    rx_queue is reached.\n  - Also, bpftrace shows that wg_packet_rx_poll for that peer is never\n    called again after reaching this state for that peer. For other\n    peers wg_packet_rx_poll does get called normally.\n  - Commit db9ae3b (\"wireguard: device: enable threaded NAPI\")\n    switched WireGuard to threaded NAPI by default. The default has\n    not been changed for triggering the issue, neither did CPU\n    hotplugging occur (i.e. 5bd8de2 (\"wireguard: queueing: always\n    return valid online CPU in wg_cpumask_choose_online()\")).\n  - The issue has been observed with stable kernels of v5.15 as well as\n    v6.1. It was reported to us that v5.10 stable is working fine, and\n    no report on v6.6 stable either (somewhat related discussion in [0]\n    though).\n  - In the WireGuard driver the only material difference between v5.10\n    stable and v5.15 stable is the switch to threaded NAPI by default.\n\n    [0] https://lore.kernel.org/netdev/CA+wXwBTT74RErDGAnj98PqS=wvdh8eM1pi4q6tTdExtjnokKqA@mail.gmail.com/\n\nBreakdown of the problem:\n\n  1) skbs arriving for decryption are enqueued to the peer-\u003erx_queue in\n     wg_packet_consume_data via wg_queue_enqueue_per_device_and_peer.\n  2) The latter only moves the skb into the MPSC peer queue if it does\n     not surpass MAX_QUEUED_PACKETS (1024) which is kept track in an\n     atomic counter via wg_prev_queue_enqueue.\n  3) In case enqueueing was successful, the skb is also queued up\n     in the device queue, round-robin picks a next online CPU, and\n     schedules the decryption worker.\n  4) The wg_packet_decrypt_worker, once scheduled, picks these up\n     from the queue, decrypts the packets and once done calls into\n     wg_queue_enqueue_per_peer_rx.\n  5) The latter updates the state to PACKET_STATE_CRYPTED on success\n     and calls napi_schedule on the per peer-\u003enapi instance.\n  6) NAPI then polls via wg_packet_rx_poll. wg_prev_queue_peek checks\n     on the peer-\u003erx_queue. It will wg_prev_queue_dequeue if the\n     queue-\u003epeeked skb was not cached yet, or just return the latter\n     otherwise. (wg_prev_queue_drop_peeked later clears the cache.)\n  7) From an ordering perspective, the peer-\u003erx_queue has skbs in order\n     while the device queue with the per-CPU worker threads from a\n     global ordering PoV can finish the decryption and signal the skb\n     PACKET_STATE_CRYPTED out of order.\n  8) A situation can be observed that the first packet coming in will\n     be stuck waiting for the decryption worker to be scheduled for\n     a longer time when the system is under pressure.\n  9) While this is the case, the other CPUs in the meantime finish\n     decryption and call into napi_schedule.\n 10) Now in wg_packet_rx_poll it picks up the first in-order skb\n     from the peer-\u003erx_queue and sees that its state is still\n     PACKET_STATE_UNCRYPTED. The NAPI poll routine then exits e\n---truncated---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable path is reached by inbound WireGuard UDP data packets processed by the kernel receive path. In severe reasonable deployments such as Kubernetes/Cilium WireGuard encryption, a remote peer/workload can drive this over the network.\nAC:L - The trigger requires high WireGuard receive load and packet/decrypt scheduling interleaving, but the attacker can repeatedly create that load with concurrent network traffic. The race is therefore attacker-influenced rather than dependent on a fixed external condition.\nPR:N - No local privileges on the vulnerable host are required to reach the receive/decrypt/NAPI path. A remote entity able to send traffic through an already configured WireGuard peer can trigger the condition.\nUI:N - No victim user action is required after the WireGuard interface and peer are operating. Network traffic alone drives the vulnerable receive path.\nS:U - The impact remains within the vulnerable kernel/networking security authority. This is not a VM escape, sandbox escape, or cross-scope boundary bypass.\nC:N - The bug is a queue/NAPI forward-progress stall, not a memory disclosure or memory corruption issue. The investigation found no read primitive or leaked data.\nI:N - The affected code stalls per-peer receive processing and drops later packets, but it does not modify attacker-chosen data or corrupt memory. No arbitrary write, control-flow hijack, or data tampering primitive is indicated.\nA:H - Once triggered, decryption for the affected WireGuard peer stops indefinitely and new connections to that peer fail because the receive queue remains full. This can fully deny availability of WireGuard-protected traffic for that peer/node until administrative recovery."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:31:56.605Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cfdb22762f903d95c36ab91e9fe6167f22fa9f6d"
        },
        {
          "url": "https://git.kernel.org/stable/c/42bc3f45425b607a5ca7b7aaaab661b54407c8f8"
        },
        {
          "url": "https://git.kernel.org/stable/c/168ee1549fa24fff2ab924a2ca7b1d85f30e062d"
        },
        {
          "url": "https://git.kernel.org/stable/c/e94b369ff82f9bc84f090f271bd78f41c9f6ab2f"
        }
      ],
      "title": "Revert \"wireguard: device: enable threaded NAPI\"",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-52945",
    "datePublished": "2026-06-24T16:26:03.313Z",
    "dateReserved": "2026-06-09T07:44:35.371Z",
    "dateUpdated": "2026-10-19T19:47:08.895Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-52945",
      "date": "2026-11-14",
      "epss": "0.00245",
      "percentile": "0.15916"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/net/wireguard/device.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "cfdb22762f903d95c36ab91e9fe6167f22fa9f6d",
                    "status": "affected",
                    "version": "18e65229a328304a7ef59899a30fd34ad73ed56b",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "42bc3f45425b607a5ca7b7aaaab661b54407c8f8",
                    "status": "affected",
                    "version": "fb978675ccfd4a93549e49624127d8332cc61cbf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "168ee1549fa24fff2ab924a2ca7b1d85f30e062d",
                    "status": "affected",
                    "version": "8c9e9cd398777fd60ba202211da1110614cb5bc5",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e94b369ff82f9bc84f090f271bd78f41c9f6ab2f",
                    "status": "affected",
                    "version": "933466fc50a8e4eb167acbd0d8ec96a078462e9c",
                    "versionType": "git"
                  },
                  {
                    "status": "affected",
                    "version": "aba544ff9ec522e120b1b3d8b32efa4e6d16d4d7",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6.16",
                    "status": "affected",
                    "version": "6.15.3",
                    "versionType": "semver"
                  }
                ]
              },
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "drivers/net/wireguard/device.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "5.15.201",
                    "status": "affected",
                    "version": "5.15.186",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.1.164",
                    "status": "affected",
                    "version": "6.1.142",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.6.127",
                    "status": "affected",
                    "version": "6.6.94",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "6.12.74",
                    "status": "affected",
                    "version": "6.12.34",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "9F2F60BD-39C5-473C-9F9E-2C640E8A78B1",
                    "versionEndExcluding": "5.15.201",
                    "versionStartIncluding": "5.15.186",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "92735AFA-4588-4AD6-A7B6-54833841E751",
                    "versionEndExcluding": "6.1.164",
                    "versionStartIncluding": "6.1.142",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "93C2DE3E-8B35-4B2D-80CD-06F8E4679CA6",
                    "versionEndExcluding": "6.6.127",
                    "versionStartIncluding": "6.6.94",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "D6C75623-EC72-42F9-97B5-799868CCFEA9",
                    "versionEndExcluding": "6.12.74",
                    "versionStartIncluding": "6.12.34",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "E1DC9D17-B1EF-44AF-87B9-9BF70F8E70C7",
                    "versionEndExcluding": "6.16",
                    "versionStartIncluding": "6.15.3",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"wireguard: device: enable threaded NAPI\"\n\nThis reverts commit 933466fc50a8e4eb167acbd0d8ec96a078462e9c which is\ncommit db9ae3b6b43c79b1ba87eea849fd65efa05b4b2e upstream.\n\nWe have had three independent production user reports in combination\nwith Cilium utilizing WireGuard as encryption underneath that k8s Pod\nE/W traffic to certain peer nodes fully stalled. The situation appears\nas follows:\n\n  - Occurs very rarely but at random times under heavy networking load.\n  - Once the issue triggers the decryption side stops working completely\n    for that WireGuard peer, other peers keep working fine. The stall\n    happens also for newly initiated connections towards that particular\n    WireGuard peer.\n  - Only the decryption side is affected, never the encryption side.\n  - Once it triggers, it never recovers and remains in this state,\n    the CPU/mem on that node looks normal, no leak, busy loop or crash.\n  - bpftrace on the affected system shows that wg_prev_queue_enqueue\n    fails, thus the MAX_QUEUED_PACKETS (1024 skbs!) for the peer\u0027s\n    rx_queue is reached.\n  - Also, bpftrace shows that wg_packet_rx_poll for that peer is never\n    called again after reaching this state for that peer. For other\n    peers wg_packet_rx_poll does get called normally.\n  - Commit db9ae3b (\"wireguard: device: enable threaded NAPI\")\n    switched WireGuard to threaded NAPI by default. The default has\n    not been changed for triggering the issue, neither did CPU\n    hotplugging occur (i.e. 5bd8de2 (\"wireguard: queueing: always\n    return valid online CPU in wg_cpumask_choose_online()\")).\n  - The issue has been observed with stable kernels of v5.15 as well as\n    v6.1. It was reported to us that v5.10 stable is working fine, and\n    no report on v6.6 stable either (somewhat related discussion in [0]\n    though).\n  - In the WireGuard driver the only material difference between v5.10\n    stable and v5.15 stable is the switch to threaded NAPI by default.\n\n    [0] https://lore.kernel.org/netdev/CA+wXwBTT74RErDGAnj98PqS=wvdh8eM1pi4q6tTdExtjnokKqA@mail.gmail.com/\n\nBreakdown of the problem:\n\n  1) skbs arriving for decryption are enqueued to the peer-\u003erx_queue in\n     wg_packet_consume_data via wg_queue_enqueue_per_device_and_peer.\n  2) The latter only moves the skb into the MPSC peer queue if it does\n     not surpass MAX_QUEUED_PACKETS (1024) which is kept track in an\n     atomic counter via wg_prev_queue_enqueue.\n  3) In case enqueueing was successful, the skb is also queued up\n     in the device queue, round-robin picks a next online CPU, and\n     schedules the decryption worker.\n  4) The wg_packet_decrypt_worker, once scheduled, picks these up\n     from the queue, decrypts the packets and once done calls into\n     wg_queue_enqueue_per_peer_rx.\n  5) The latter updates the state to PACKET_STATE_CRYPTED on success\n     and calls napi_schedule on the per peer-\u003enapi instance.\n  6) NAPI then polls via wg_packet_rx_poll. wg_prev_queue_peek checks\n     on the peer-\u003erx_queue. It will wg_prev_queue_dequeue if the\n     queue-\u003epeeked skb was not cached yet, or just return the latter\n     otherwise. (wg_prev_queue_drop_peeked later clears the cache.)\n  7) From an ordering perspective, the peer-\u003erx_queue has skbs in order\n     while the device queue with the per-CPU worker threads from a\n     global ordering PoV can finish the decryption and signal the skb\n     PACKET_STATE_CRYPTED out of order.\n  8) A situation can be observed that the first packet coming in will\n     be stuck waiting for the decryption worker to be scheduled for\n     a longer time when the system is under pressure.\n  9) While this is the case, the other CPUs in the meantime finish\n     decryption and call into napi_schedule.\n 10) Now in wg_packet_rx_poll it picks up the first in-order skb\n     from the peer-\u003erx_queue and sees that its state is still\n     PACKET_STATE_UNCRYPTED. The NAPI poll routine then exits e\n---truncated---"
          }
        ],
        "id": "CVE-2026-52945",
        "lastModified": "2026-10-19T20:18:49.010",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 3.6,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-52945",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-16T15:23:09.444431Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-06-24T17:17:04.430",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/168ee1549fa24fff2ab924a2ca7b1d85f30e062d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/42bc3f45425b607a5ca7b7aaaab661b54407c8f8"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/cfdb22762f903d95c36ab91e9fe6167f22fa9f6d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/e94b369ff82f9bc84f090f271bd78f41c9f6ab2f"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-362"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-11-12T05:55:28+00:00",
      "cve": "CVE-2026-52945",
      "id": "CVE-2026-52945",
      "initial_release_date": "2026-06-24T00:00:00+00:00",
      "product_status:fixed": "1338",
      "product_status:known_affected": "22",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Revert \"wireguard: device: enable threaded NAPI\"",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52945.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-10-17T00:24:37Z",
      "cve": "CVE-2026-52945",
      "id": "CVE-2026-52945",
      "initial_release_date": "2026-06-26T02:15:06Z",
      "product_status:known_affected": "0",
      "product_status:known_not_affected": "385",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-52945",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-52945.json",
      "version": "4"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-52945",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-16T15:23:09.444431Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-362",
                    "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-16T15:23:10.152Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "drivers/net/wireguard/device.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "cfdb22762f903d95c36ab91e9fe6167f22fa9f6d",
                  "status": "affected",
                  "version": "18e65229a328304a7ef59899a30fd34ad73ed56b",
                  "versionType": "git"
                },
                {
                  "lessThan": "42bc3f45425b607a5ca7b7aaaab661b54407c8f8",
                  "status": "affected",
                  "version": "fb978675ccfd4a93549e49624127d8332cc61cbf",
                  "versionType": "git"
                },
                {
                  "lessThan": "168ee1549fa24fff2ab924a2ca7b1d85f30e062d",
                  "status": "affected",
                  "version": "8c9e9cd398777fd60ba202211da1110614cb5bc5",
                  "versionType": "git"
                },
                {
                  "lessThan": "e94b369ff82f9bc84f090f271bd78f41c9f6ab2f",
                  "status": "affected",
                  "version": "933466fc50a8e4eb167acbd0d8ec96a078462e9c",
                  "versionType": "git"
                },
                {
                  "status": "affected",
                  "version": "aba544ff9ec522e120b1b3d8b32efa4e6d16d4d7",
                  "versionType": "git"
                },
                {
                  "lessThan": "6.16",
                  "status": "affected",
                  "version": "6.15.3",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "drivers/net/wireguard/device.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "5.15.201",
                  "status": "affected",
                  "version": "5.15.186",
                  "versionType": "semver"
                },
                {
                  "lessThan": "6.1.164",
                  "status": "affected",
                  "version": "6.1.142",
                  "versionType": "semver"
                },
                {
                  "lessThan": "6.6.127",
                  "status": "affected",
                  "version": "6.6.94",
                  "versionType": "semver"
                },
                {
                  "lessThan": "6.12.74",
                  "status": "affected",
                  "version": "6.12.34",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.15.201",
                      "versionStartIncluding": "5.15.186",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.1.164",
                      "versionStartIncluding": "6.1.142",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.127",
                      "versionStartIncluding": "6.6.94",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.74",
                      "versionStartIncluding": "6.12.34",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionStartIncluding": "6.15.3",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"wireguard: device: enable threaded NAPI\"\n\nThis reverts commit 933466fc50a8e4eb167acbd0d8ec96a078462e9c which is\ncommit db9ae3b6b43c79b1ba87eea849fd65efa05b4b2e upstream.\n\nWe have had three independent production user reports in combination\nwith Cilium utilizing WireGuard as encryption underneath that k8s Pod\nE/W traffic to certain peer nodes fully stalled. The situation appears\nas follows:\n\n  - Occurs very rarely but at random times under heavy networking load.\n  - Once the issue triggers the decryption side stops working completely\n    for that WireGuard peer, other peers keep working fine. The stall\n    happens also for newly initiated connections towards that particular\n    WireGuard peer.\n  - Only the decryption side is affected, never the encryption side.\n  - Once it triggers, it never recovers and remains in this state,\n    the CPU/mem on that node looks normal, no leak, busy loop or crash.\n  - bpftrace on the affected system shows that wg_prev_queue_enqueue\n    fails, thus the MAX_QUEUED_PACKETS (1024 skbs!) for the peer\u0027s\n    rx_queue is reached.\n  - Also, bpftrace shows that wg_packet_rx_poll for that peer is never\n    called again after reaching this state for that peer. For other\n    peers wg_packet_rx_poll does get called normally.\n  - Commit db9ae3b (\"wireguard: device: enable threaded NAPI\")\n    switched WireGuard to threaded NAPI by default. The default has\n    not been changed for triggering the issue, neither did CPU\n    hotplugging occur (i.e. 5bd8de2 (\"wireguard: queueing: always\n    return valid online CPU in wg_cpumask_choose_online()\")).\n  - The issue has been observed with stable kernels of v5.15 as well as\n    v6.1. It was reported to us that v5.10 stable is working fine, and\n    no report on v6.6 stable either (somewhat related discussion in [0]\n    though).\n  - In the WireGuard driver the only material difference between v5.10\n    stable and v5.15 stable is the switch to threaded NAPI by default.\n\n    [0] https://lore.kernel.org/netdev/CA+wXwBTT74RErDGAnj98PqS=wvdh8eM1pi4q6tTdExtjnokKqA@mail.gmail.com/\n\nBreakdown of the problem:\n\n  1) skbs arriving for decryption are enqueued to the peer-\u003erx_queue in\n     wg_packet_consume_data via wg_queue_enqueue_per_device_and_peer.\n  2) The latter only moves the skb into the MPSC peer queue if it does\n     not surpass MAX_QUEUED_PACKETS (1024) which is kept track in an\n     atomic counter via wg_prev_queue_enqueue.\n  3) In case enqueueing was successful, the skb is also queued up\n     in the device queue, round-robin picks a next online CPU, and\n     schedules the decryption worker.\n  4) The wg_packet_decrypt_worker, once scheduled, picks these up\n     from the queue, decrypts the packets and once done calls into\n     wg_queue_enqueue_per_peer_rx.\n  5) The latter updates the state to PACKET_STATE_CRYPTED on success\n     and calls napi_schedule on the per peer-\u003enapi instance.\n  6) NAPI then polls via wg_packet_rx_poll. wg_prev_queue_peek checks\n     on the peer-\u003erx_queue. It will wg_prev_queue_dequeue if the\n     queue-\u003epeeked skb was not cached yet, or just return the latter\n     otherwise. (wg_prev_queue_drop_peeked later clears the cache.)\n  7) From an ordering perspective, the peer-\u003erx_queue has skbs in order\n     while the device queue with the per-CPU worker threads from a\n     global ordering PoV can finish the decryption and signal the skb\n     PACKET_STATE_CRYPTED out of order.\n  8) A situation can be observed that the first packet coming in will\n     be stuck waiting for the decryption worker to be scheduled for\n     a longer time when the system is under pressure.\n  9) While this is the case, the other CPUs in the meantime finish\n     decryption and call into napi_schedule.\n 10) Now in wg_packet_rx_poll it picks up the first in-order skb\n     from the peer-\u003erx_queue and sees that its state is still\n     PACKET_STATE_UNCRYPTED. The NAPI poll routine then exits e\n---truncated---"
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - The vulnerable path is reached by inbound WireGuard UDP data packets processed by the kernel receive path. In severe reasonable deployments such as Kubernetes/Cilium WireGuard encryption, a remote peer/workload can drive this over the network.\nAC:L - The trigger requires high WireGuard receive load and packet/decrypt scheduling interleaving, but the attacker can repeatedly create that load with concurrent network traffic. The race is therefore attacker-influenced rather than dependent on a fixed external condition.\nPR:N - No local privileges on the vulnerable host are required to reach the receive/decrypt/NAPI path. A remote entity able to send traffic through an already configured WireGuard peer can trigger the condition.\nUI:N - No victim user action is required after the WireGuard interface and peer are operating. Network traffic alone drives the vulnerable receive path.\nS:U - The impact remains within the vulnerable kernel/networking security authority. This is not a VM escape, sandbox escape, or cross-scope boundary bypass.\nC:N - The bug is a queue/NAPI forward-progress stall, not a memory disclosure or memory corruption issue. The investigation found no read primitive or leaked data.\nI:N - The affected code stalls per-peer receive processing and drops later packets, but it does not modify attacker-chosen data or corrupt memory. No arbitrary write, control-flow hijack, or data tampering primitive is indicated.\nA:H - Once triggered, decryption for the affected WireGuard peer stops indefinitely and new connections to that peer fail because the receive queue remains full. This can fully deny availability of WireGuard-protected traffic for that peer/node until administrative recovery."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T12:31:56.605Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/cfdb22762f903d95c36ab91e9fe6167f22fa9f6d"
            },
            {
              "url": "https://git.kernel.org/stable/c/42bc3f45425b607a5ca7b7aaaab661b54407c8f8"
            },
            {
              "url": "https://git.kernel.org/stable/c/168ee1549fa24fff2ab924a2ca7b1d85f30e062d"
            },
            {
              "url": "https://git.kernel.org/stable/c/e94b369ff82f9bc84f090f271bd78f41c9f6ab2f"
            }
          ],
          "title": "Revert \"wireguard: device: enable threaded NAPI\"",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2026-52945",
        "datePublished": "2026-06-24T16:26:03.313Z",
        "dateReserved": "2026-06-09T07:44:35.371Z",
        "dateUpdated": "2026-10-19T19:47:08.895Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.