{"id":"CVE-2026-72125","state":"PUBLISHED","title":"can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER\n\nisotp_release() looked up the bound network device via dev_get_by_index()\nusing the stored ifindex. During device unregistration the device is\nunlisted from the ifindex hash before the NETDEV_UNREGISTER notifier\nchain runs, so a concurrent isotp_release() could find no device, skip\ncan_rx_unregister() entirely, and still proceed to free the socket.\nSince isotp_release() had already removed itself from the isotp\nnotifier list at that point, isotp_notify() would never get a chance to\nclean up either, leaving a stale CAN filter that keeps pointing at the\nfreed socket.\n\nFix this the same way raw.c already does: hold a tracked reference to\nthe bound net_device in the socket (so->dev/so->dev_tracker) from\nbind() onward instead of re-resolving it from the ifindex, and\nserialize bind()/release() with rtnl_lock() so that so->dev is always\nconsistent with what the NETDEV_UNREGISTER notifier sees. so->dev\nstays valid regardless of ifindex-hash unlisting, and is only ever\ncleared by whichever of isotp_release()/isotp_notify() gets there\nfirst, so the filter is always removed exactly once.\n\nisotp_bind() now rejects a (re)bind with -EAGAIN while so->[tx|rx].state\nisn't ISOTP_IDLE yet, so a timer left running by a prior\nNETDEV_UNREGISTER can't act on a newly bound so->ifindex. Both checks\nshare the same lock_sock() section, so there is no window in which a\nconcurrent isotp_notify() clearing so->bound could be missed.","publishedAt":"2026-08-15T05:53:02.905Z","updatedAt":"2026-10-16T18:44:57.938Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"f311bbb29bb06aaab69ba45a6e4b11323d20b8f9","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"8e018f4335590460ebcf0c2b493ed38ba1a35204","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"33b9cd9245e2a4b800f99ed1cc53d64960614152","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"43884dc7963beef2328f507f4fe680bdc173eb80","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"7bef39ba76eb7307ed22a50329e0f5776dbeda58","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"e442b62ba5a7756c17e05a77b32cdd085a2b6138","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"20bab8b88baac140ca3701116e1d486c7f51e311","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/isotp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/isotp.c"]}],"references":["https://git.kernel.org/stable/c/f311bbb29bb06aaab69ba45a6e4b11323d20b8f9","https://git.kernel.org/stable/c/8e018f4335590460ebcf0c2b493ed38ba1a35204","https://git.kernel.org/stable/c/33b9cd9245e2a4b800f99ed1cc53d64960614152","https://git.kernel.org/stable/c/0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96","https://git.kernel.org/stable/c/43884dc7963beef2328f507f4fe680bdc173eb80","https://git.kernel.org/stable/c/7bef39ba76eb7307ed22a50329e0f5776dbeda58","https://git.kernel.org/stable/c/e442b62ba5a7756c17e05a77b32cdd085a2b6138","https://git.kernel.org/stable/c/20bab8b88baac140ca3701116e1d486c7f51e311"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/72xxx/CVE-2026-72125.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-72125","state":"PUBLISHED","datePublished":"2026-08-15T05:53:02.905Z","dateUpdated":"2026-10-16T18:44:57.938Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-09T03:40:39.907Z"},"containers":{"cna":{"title":"can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER\n\nisotp_release() looked up the bound network device via dev_get_by_index()\nusing the stored ifindex. During device unregistration the device is\nunlisted from the ifindex hash before the NETDEV_UNREGISTER notifier\nchain runs, so a concurrent isotp_release() could find no device, skip\ncan_rx_unregister() entirely, and still proceed to free the socket.\nSince isotp_release() had already removed itself from the isotp\nnotifier list at that point, isotp_notify() would never get a chance to\nclean up either, leaving a stale CAN filter that keeps pointing at the\nfreed socket.\n\nFix this the same way raw.c already does: hold a tracked reference to\nthe bound net_device in the socket (so->dev/so->dev_tracker) from\nbind() onward instead of re-resolving it from the ifindex, and\nserialize bind()/release() with rtnl_lock() so that so->dev is always\nconsistent with what the NETDEV_UNREGISTER notifier sees. so->dev\nstays valid regardless of ifindex-hash unlisting, and is only ever\ncleared by whichever of isotp_release()/isotp_notify() gets there\nfirst, so the filter is always removed exactly once.\n\nisotp_bind() now rejects a (re)bind with -EAGAIN while so->[tx|rx].state\nisn't ISOTP_IDLE yet, so a timer left running by a prior\nNETDEV_UNREGISTER can't act on a newly bound so->ifindex. Both checks\nshare the same lock_sock() section, so there is no window in which a\nconcurrent isotp_notify() clearing so->bound could be missed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"f311bbb29bb06aaab69ba45a6e4b11323d20b8f9","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"8e018f4335590460ebcf0c2b493ed38ba1a35204","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"33b9cd9245e2a4b800f99ed1cc53d64960614152","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"43884dc7963beef2328f507f4fe680bdc173eb80","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"7bef39ba76eb7307ed22a50329e0f5776dbeda58","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"e442b62ba5a7756c17e05a77b32cdd085a2b6138","versionType":"git"},{"version":"e057dd3fc20ffb3d7f150af46542a51b59b90127","status":"affected","lessThan":"20bab8b88baac140ca3701116e1d486c7f51e311","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/isotp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/isotp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f311bbb29bb06aaab69ba45a6e4b11323d20b8f9"},{"url":"https://git.kernel.org/stable/c/8e018f4335590460ebcf0c2b493ed38ba1a35204"},{"url":"https://git.kernel.org/stable/c/33b9cd9245e2a4b800f99ed1cc53d64960614152"},{"url":"https://git.kernel.org/stable/c/0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96"},{"url":"https://git.kernel.org/stable/c/43884dc7963beef2328f507f4fe680bdc173eb80"},{"url":"https://git.kernel.org/stable/c/7bef39ba76eb7307ed22a50329e0f5776dbeda58"},{"url":"https://git.kernel.org/stable/c/e442b62ba5a7756c17e05a77b32cdd085a2b6138"},{"url":"https://git.kernel.org/stable/c/20bab8b88baac140ca3701116e1d486c7f51e311"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires local AF_CAN ISO-TP socket operations (socket/bind/close) racing NETDEV_UNREGISTER on the bound CAN interface; stale-filter UAF is triggered via local frame injection or an existing bound interface, not a remote IP/network service.\nAC:L - The attacker controls both sides of the race by concurrently closing the ISO-TP socket and unregistering the bound CAN device (e.g., vcan create/delete with CAP_NET_ADMIN in a user namespace), and can retry until the stale RX filter is left on a freed socket.\nPR:L - No init-namespace root is required: any local user can open CAN_ISOTP sockets, and CAP_NET_ADMIN obtainable in user namespaces suffices to create/delete vcan and drive the unregister path used in automotive/embedded ISO-TP (UDS) deployments.\nUI:N - No victim interaction is needed; the use-after-free is triggered by the attacker's own concurrent close()/NETDEV_UNREGISTER operations and subsequent CAN frames sent to the bound IDs.\nS:U - Impact is kernel heap corruption and potential privilege escalation within the same OS security boundary; it does not inherently cross VM, container, or IOMMU isolation boundaries.\nC:H - A stale can_rx filter keeps calling isotp_rcv()/isotp_rcv_echo() with a freed isotp_sock, enabling reads of reallocated slab contents through socket state, sock_queue_rcv_skb(), and protocol parsing on attacker-influenced memory.\nI:H - The UAF path performs extensive writes to freed socket state (RX/TX buffers, timers, generation counters) and can emit CAN traffic, providing primitives for heap shaping and control-flow hijack rather than a crash-only fault.\nA:H - Use-after-free in softirq CAN receive callbacks commonly causes kernel oops/panic from dereferencing or writing freed isotp_sock/timer state, even before reliable exploitation."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:36:23.877Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-72125","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:42:17.799188Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:44:57.938Z"}}]}}}