Vulnerability-Lookup

FKIE_CVE-2026-74742

Vulnerability from fkie_nvd - Published: 2026-08-26 15:16 - Updated: 2026-08-27 06:17

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: veth: fix queue index used to wake the peer txq in veth_poll veth_poll() derives the index of the peer TX queue to wake from rq->xdp_rxq.queue_index. That field is only initialized by xdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an XDP program is attached. On the plain GRO/NAPI path (veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so queue_index stays 0 for every queue, as priv->rq is zero-allocated. So in a multi-queue setup with GRO enabled and no XDP program attached, every NAPI instance looks at the peer's TX queue 0. If veth_xmit() stops peer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing ever wakes it again: the poller draining queue 1 wakes queue 0 instead. veth implements no ndo_tx_timeout, so the netdev watchdog does not kick in either, and the queue stays stopped indefinitely. Derive the index from the position of the rq within priv->rq instead, which is correct regardless of whether XDP was ever enabled. Scripts to reproduce the stall are available at https://github.com/netoptimizer/veth-backpressure-performance-testing

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b662a1fb4f3a5ea19bac24eea8315b1d05be51e7",
              "status": "affected",
              "version": "9fe31b3f314534e238aa6d0b6fb492134cbcf8be",
              "versionType": "git"
            },
            {
              "lessThan": "73f8dd22b1e533a99ecc3f9b5de6c6daccaecace",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "90bb11fb29d3c55a2c46dc7c386d096b286e7fcf",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "60db47f02bfa2aa688938aa199117ec4f8e31d23",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "6.12.105",
              "status": "affected",
              "version": "6.12.61",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq-\u003exdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv-\u003erq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer\u0027s TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv-\u003erq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing"
    }
  ],
  "id": "CVE-2026-74742",
  "lastModified": "2026-08-27T06:17:23.867",
  "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"
      }
    ]
  },
  "published": "2026-08-26T15:16:52.990",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-74742 (GCVE-0-2026-74742)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:36 – Updated: 2026-08-27 05:01

Title

veth: fix queue index used to wake the peer txq in veth_poll

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/b662a1fb4f3a5ea19…
https://git.kernel.org/stable/c/73f8dd22b1e533a99…
https://git.kernel.org/stable/c/90bb11fb29d3c55a2…
https://git.kernel.org/stable/c/60db47f02bfa2aa68…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9fe31b3f314534e238aa6d0b6fb492134cbcf8be , < b662a1fb4f3a5ea19bac24eea8315b1d05be51e7 (git) Affected: dc82a33297fc2c58cb0b2b008d728668d45c0f6a , < 73f8dd22b1e533a99ecc3f9b5de6c6daccaecace (git) Affected: dc82a33297fc2c58cb0b2b008d728668d45c0f6a , < 90bb11fb29d3c55a2c46dc7c386d096b286e7fcf (git) Affected: dc82a33297fc2c58cb0b2b008d728668d45c0f6a , < 60db47f02bfa2aa688938aa199117ec4f8e31d23 (git) Affected: 6.12.61 , < 6.12.105 (semver)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.12.105 , ≤ 6.12.* (semver) Unaffected: 6.18.46 , ≤ 6.18.* (semver) Unaffected: 7.1.10 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b662a1fb4f3a5ea19bac24eea8315b1d05be51e7",
              "status": "affected",
              "version": "9fe31b3f314534e238aa6d0b6fb492134cbcf8be",
              "versionType": "git"
            },
            {
              "lessThan": "73f8dd22b1e533a99ecc3f9b5de6c6daccaecace",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "90bb11fb29d3c55a2c46dc7c386d096b286e7fcf",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "60db47f02bfa2aa688938aa199117ec4f8e31d23",
              "status": "affected",
              "version": "dc82a33297fc2c58cb0b2b008d728668d45c0f6a",
              "versionType": "git"
            },
            {
              "lessThan": "6.12.105",
              "status": "affected",
              "version": "6.12.61",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.105",
                  "versionStartIncluding": "6.12.61",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.46",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.10",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix queue index used to wake the peer txq in veth_poll\n\nveth_poll() derives the index of the peer TX queue to wake from\nrq-\u003exdp_rxq.queue_index. That field is only initialized by\nxdp_rxq_info_reg() in veth_enable_xdp_range(), which runs only when an\nXDP program is attached. On the plain GRO/NAPI path\n(veth_napi_enable_range()) xdp_rxq_info_reg() is never called, so\nqueue_index stays 0 for every queue, as priv-\u003erq is zero-allocated.\n\nSo in a multi-queue setup with GRO enabled and no XDP program attached,\nevery NAPI instance looks at the peer\u0027s TX queue 0. If veth_xmit() stops\npeer TX queue 1 because the ptr_ring is full (NETDEV_TX_BUSY), nothing\never wakes it again: the poller draining queue 1 wakes queue 0 instead.\nveth implements no ndo_tx_timeout, so the netdev watchdog does not kick\nin either, and the queue stays stopped indefinitely.\n\nDerive the index from the position of the rq within priv-\u003erq instead,\nwhich is correct regardless of whether XDP was ever enabled.\n\nScripts to reproduce the stall are available at\nhttps://github.com/netoptimizer/veth-backpressure-performance-testing"
        }
      ],
      "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 - Remote packets routed, NATed, or bridged into a suitably configured container veth reach veth_xmit() and veth_poll() through normal netdev transmit and NAPI softirq paths; no local syscall or physical access is required.\nAC:L - Sustained multi-flow traffic can deterministically fill the ptr_ring on a non-zero RX queue and drive its NAPI poller; waking queue 0 instead of the stopped queue is a logic bug, not a race or layout-dependent condition the attacker cannot control.\nPR:N - Multi-queue veth, GRO, and a non-noqueue qdisc are infrastructure prerequisites, not attacker privileges; forwarded packets traverse veth_xmit/veth_poll with no capability or authentication check, as with CVE-2025-68232 in the same backpressure code.\nUI:N - Exploitation requires only attacker-generated network traffic to drive backpressure on the veth pair; no victim action such as mounting filesystems or opening files is necessary.\nS:U - The defect leaves transmit queues in DRV_XOFF within the host kernel veth driver and does not cross VM, IOMMU, or sandbox security boundaries.\nC:N - The bug only mis-associates NAPI poll instances with peer TX queue indices during wakeup; there is no out-of-bounds access, use-after-free, or other memory read primitive.\nI:N - No memory corruption, arbitrary write, packet tampering, or control-flow influence occurs; the failure is limited to incorrect queue state management on the transmit path.\nA:H - When a non-zero peer TX queue is stopped for a full ptr_ring, veth_poll() never wakes it again and veth has no ndo_tx_timeout recovery, causing an indefinite transmit stall and persistent loss of connectivity on affected queues."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:01:02.886Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b662a1fb4f3a5ea19bac24eea8315b1d05be51e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/73f8dd22b1e533a99ecc3f9b5de6c6daccaecace"
        },
        {
          "url": "https://git.kernel.org/stable/c/90bb11fb29d3c55a2c46dc7c386d096b286e7fcf"
        },
        {
          "url": "https://git.kernel.org/stable/c/60db47f02bfa2aa688938aa199117ec4f8e31d23"
        }
      ],
      "title": "veth: fix queue index used to wake the peer txq in veth_poll",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74742",
    "datePublished": "2026-08-26T14:36:53.580Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-27T05:01:02.886Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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