CVE-2026-74255 (GCVE-0-2026-74255)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:45
VLAI
Title
tipc: fix UAF in tipc_l2_send_msg()
Summary
In the Linux kernel, the following vulnerability has been resolved: tipc: fix UAF in tipc_l2_send_msg() Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg(). The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished. The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers. Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net(). This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 ("tipc: make bearer packet filtering generic") to call tipc_node_delete_links() (which needs the pointer) before disable_media(). https: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 282b3a056225b35024246f63feb91d769d714dad , < 609ced2301be1df7e7ed2ef47d1d916674e6ba3b (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < 71aafa16d79b107b33837f60b6cbc7d0cb8c5708 (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < f4002f1c669cc02e3763f479fc25ff1dfa9e2420 (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < 50ff092633b06382e5091dd5b093ce943d4ac2f9 (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < aef12b5ce793dea6b3a97a58fd0f946000ae8945 (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < 0d8a12d7143126afdf9fbe2e3d438650dd6603ed (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < 35e0297a93c3c34a3924eeef816c03504e3ab5c5 (git)
Affected: 282b3a056225b35024246f63feb91d769d714dad , < f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.4
Unaffected: 0 , < 4.4 (semver)
Unaffected: 5.10.261 , ≤ 5.10.* (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/tipc/bearer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "609ced2301be1df7e7ed2ef47d1d916674e6ba3b",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "71aafa16d79b107b33837f60b6cbc7d0cb8c5708",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "f4002f1c669cc02e3763f479fc25ff1dfa9e2420",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "50ff092633b06382e5091dd5b093ce943d4ac2f9",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "aef12b5ce793dea6b3a97a58fd0f946000ae8945",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "0d8a12d7143126afdf9fbe2e3d438650dd6603ed",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "35e0297a93c3c34a3924eeef816c03504e3ab5c5",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            },
            {
              "lessThan": "f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6",
              "status": "affected",
              "version": "282b3a056225b35024246f63feb91d769d714dad",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/tipc/bearer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.4"
            },
            {
              "lessThan": "4.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "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": "5.10.261",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix UAF in tipc_l2_send_msg()\n\nSyzbot reported a slab-use-after-free in ipvlan_hard_header() when\ncalled from tipc_l2_send_msg().\n\nThe root cause is that tipc_disable_l2_media() calls synchronize_net()\nwhile b-\u003emedia_ptr is still valid. This allows concurrent RCU readers\nto obtain the device pointer after synchronize_net() has finished.\nThe pointer is cleared later in bearer_disable(), but without any\nsubsequent synchronization, allowing the device to be freed while\nstill in use by readers.\n\nFix this by clearing b-\u003emedia_ptr in tipc_disable_l2_media() before\ncalling synchronize_net().\n\nThis is safe to do now because the call order in bearer_disable()\nwas reversed in 0d051bf93c06 (\"tipc: make bearer packet filtering generic\")\nto call tipc_node_delete_links() (which needs the pointer) before\ndisable_media().\n\nhttps: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - tipc_l2_send_msg is reached from tipc_bearer_xmit during L2 TIPC protocol handling; remote ETH_P_TIPC frames on cluster/datacenter L2 networks drive outbound transmission that races with bearer teardown in tipc_disable_l2_media.\nAC:L - The UAF window is a race where attackers control both sides by flooding TIPC Ethernet traffic while bearer disable runs and by concurrently triggering bearer teardown; syzbot reliably reproduced this without attacker-uncontrollable timing.\nPR:N - An unauthenticated remote attacker only needs to send TIPC L2 frames on a segment with an active bearer; bearer_disable teardown during cluster failover, netdev unregister, or node shutdown creates the required concurrent disable without attacker-local privileges.\nUI:N - No victim user action is required; exploitation is triggered by remote protocol traffic concurrent with automated or administrative bearer/interface teardown events.\nS:U - Impact is kernel slab memory corruption and potential privilege escalation within the same kernel security boundary, not a cross-VM or cross-namespace escape.\nC:H - Slab use-after-free of a net_device structure via ipvlan_hard_header enables reading freed kernel heap memory and can be leveraged for arbitrary kernel memory disclosure.\nI:H - UAF on net_device during dev_hard_header allows heap grooming and control of freed object contents, enabling arbitrary kernel writes and potential code execution.\nA:H - The UAF causes kernel oops/panic (as reported by syzbot in ipvlan_hard_header) and can be triggered repeatedly to deny service on cluster nodes."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:03.215Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/609ced2301be1df7e7ed2ef47d1d916674e6ba3b"
        },
        {
          "url": "https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708"
        },
        {
          "url": "https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420"
        },
        {
          "url": "https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9"
        },
        {
          "url": "https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945"
        },
        {
          "url": "https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6"
        }
      ],
      "title": "tipc: fix UAF in tipc_l2_send_msg()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74255",
    "datePublished": "2026-08-15T05:57:34.293Z",
    "dateReserved": "2026-08-15T05:44:03.876Z",
    "dateUpdated": "2026-08-17T05:45:03.215Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74255",
      "date": "2026-08-17",
      "epss": "0.00506",
      "percentile": "0.40908"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74255\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:24.627\",\"lastModified\":\"2026-08-17T06:19:18.780\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\ntipc: fix UAF in tipc_l2_send_msg()\\n\\nSyzbot reported a slab-use-after-free in ipvlan_hard_header() when\\ncalled from tipc_l2_send_msg().\\n\\nThe root cause is that tipc_disable_l2_media() calls synchronize_net()\\nwhile b-\u003emedia_ptr is still valid. This allows concurrent RCU readers\\nto obtain the device pointer after synchronize_net() has finished.\\nThe pointer is cleared later in bearer_disable(), but without any\\nsubsequent synchronization, allowing the device to be freed while\\nstill in use by readers.\\n\\nFix this by clearing b-\u003emedia_ptr in tipc_disable_l2_media() before\\ncalling synchronize_net().\\n\\nThis is safe to do now because the call order in bearer_disable()\\nwas reversed in 0d051bf93c06 (\\\"tipc: make bearer packet filtering generic\\\")\\nto call tipc_node_delete_links() (which needs the pointer) before\\ndisable_media().\\n\\nhttps: //lore.kernel.org/netdev/6a2c1007.428ffe26.258b27.015d.GAE@google.com/T/#u\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/tipc/bearer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"609ced2301be1df7e7ed2ef47d1d916674e6ba3b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"71aafa16d79b107b33837f60b6cbc7d0cb8c5708\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"f4002f1c669cc02e3763f479fc25ff1dfa9e2420\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"50ff092633b06382e5091dd5b093ce943d4ac2f9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"aef12b5ce793dea6b3a97a58fd0f946000ae8945\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"0d8a12d7143126afdf9fbe2e3d438650dd6603ed\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"35e0297a93c3c34a3924eeef816c03504e3ab5c5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"282b3a056225b35024246f63feb91d769d714dad\",\"lessThan\":\"f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/tipc/bearer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.4\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.4\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.261\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.212\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0d8a12d7143126afdf9fbe2e3d438650dd6603ed\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/35e0297a93c3c34a3924eeef816c03504e3ab5c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/50ff092633b06382e5091dd5b093ce943d4ac2f9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/609ced2301be1df7e7ed2ef47d1d916674e6ba3b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/71aafa16d79b107b33837f60b6cbc7d0cb8c5708\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/aef12b5ce793dea6b3a97a58fd0f946000ae8945\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f4002f1c669cc02e3763f479fc25ff1dfa9e2420\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.


Detection rules are retrieved from Rulezet.