{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74255", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.876Z", "datePublished": "2026-08-15T05:57:34.293Z", "dateUpdated": "2026-08-17T05:45:03.215Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:45:03.215Z" }, "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->media_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->media_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": { "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" }, "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/bearer.c" ], "versions": [ { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "609ced2301be1df7e7ed2ef47d1d916674e6ba3b", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "71aafa16d79b107b33837f60b6cbc7d0cb8c5708", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "f4002f1c669cc02e3763f479fc25ff1dfa9e2420", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "50ff092633b06382e5091dd5b093ce943d4ac2f9", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "aef12b5ce793dea6b3a97a58fd0f946000ae8945", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "0d8a12d7143126afdf9fbe2e3d438650dd6603ed", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "35e0297a93c3c34a3924eeef816c03504e3ab5c5", "status": "affected", "versionType": "git" }, { "version": "282b3a056225b35024246f63feb91d769d714dad", "lessThan": "f4c3d89fc986b0da196ddfc6cfe0ea5d5d08bec6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/bearer.c" ], "versions": [ { "version": "4.4", "status": "affected" }, { "version": "0", "lessThan": "4.4", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.4", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }