{"id":"CVE-2026-72123","revision":null,"records":[{"revision":"9c472e70e4c64efcb434d3dafecd1eaf","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72123","aliases":[],"title":"can: bcm: defer rx_op deallocation to workqueue to fix thrtimer UAF","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: defer rx_op deallocation to workqueue to fix thrtimer UAF\n\nCommit f1b4e32aca08 (\"can: bcm: use call_rcu() instead of costly\nsynchronize_rcu()\") replaced synchronize_rcu() in bcm_delete_rx_op()\nwith call_rcu() and introduced the RX_NO_AUTOTIMER flag.\n\nHowever, this flag check was omitted for thrtimer in the packet rx\nfast-path. During BCM RX operation teardown, a concurrent RCU reader\n(bcm_rx_handler) can race and re-arm thrtimer via\nbcm_rx_update_and_send() after call_rcu() has been scheduled. Once\nthe RCU grace period elapses, bcm_op is freed. The subsequently\nfiring thrtimer then dereferences the deallocated op, causing a UAF.\n\nAdding flag checks to the rx fast-path (bcm_rx_update_and_send) does not\nfully close the TOCTOU race and introduces latency for every CAN frame.\nConversely, calling hrtimer_cancel() directly inside the RCU callback\n(softirq context) is fatal as hrtimer_cancel() can sleep, triggering\na \"scheduling while atomic\" panic.\n\nResolve this by deferring the timer cancellation and memory free to a\ndedicated unbound workqueue (bcm_wq). The RCU callback now queues a\nwork item to bcm_wq, which safely cancels both timers and deallocates\nmemory in sleepable process context. A dedicated workqueue is used to\nprevent system-wide WQ saturation and is cleanly flushed/destroyed\non module unload to avoid rmmod page faults.\n\nSince the deferred work can now outlive the calling context by an\nunbounded amount, also take a reference on op->sk when it is assigned\nand drop it only once the deferred work has cancelled both timers, so a\nsocket can no longer be freed out from under a still-armed timer whose\ncallback (bcm_send_to_user()) dereferences op->sk.","state":0,"publishedAt":"2026-08-15T05:53:01.433+00:00","modifiedAt":"2026-10-16T18:44:57.598+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/can/bcm.c\"\n ],\n \"versions\": [\n {\n \"version\": \"85cd41070df992d3c0dfd828866fdd243d3b774a\",\n \"lessThan\": \"de5fce46637de05bef56ec08528127676eb6fc9b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f34f2a18e47b73e48f90a757e1f4aaa8c7d665a1\",\n \"lessThan\": \"036a8c320ca11bc912e8027adcfad14b326f067e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"3cf4fd5316f449811d8baf1bc6978ef5a7b743a9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"4177762f70646ac48a2af382e45a795cbd295198\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"6fd08e8d826c3aa4cc7021f5f9cdbb7fa7441d3f\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"cd830e0bc25ee2d38cbfbdbb3cd77c5f53b2b6d5\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"ce2d4b121fb7545e1ed588e860c8e5fd5ad45224\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"f1b4e32aca0811aa011c76e5d6cf2fa19224b386\",\n \"lessThan\": \"68973f9db76144825e4f35dfdc80fb8279eb2d57\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"fbac09a3b8890003c0c55294c00709f3ae5501bb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"5b48f5711f1c630841ab78dcc061de902f0e37bf\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"edb4baffb9483141a50fb7f7146cfe4a4c0c2db8\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"5.10.130\",\n \"lessThan\": \"5.10.265\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.54\",\n \"lessThan\": \"5.15.216\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.19.252\",\n \"lessThan\": \"4.20\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.205\",\n \"lessThan\": \"5.5\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.18.11\",\n \"lessThan\": \"5.19\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/can/bcm.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.19\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.19\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.265\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.216\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.178\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.145\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.97\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.40\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1.5\",\n \"lessThanOrEqual\": \"7.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/de5fce46637de05bef56ec08528127676eb6fc9b","https://git.kernel.org/stable/c/036a8c320ca11bc912e8027adcfad14b326f067e","https://git.kernel.org/stable/c/3cf4fd5316f449811d8baf1bc6978ef5a7b743a9","https://git.kernel.org/stable/c/4177762f70646ac48a2af382e45a795cbd295198","https://git.kernel.org/stable/c/6fd08e8d826c3aa4cc7021f5f9cdbb7fa7441d3f","https://git.kernel.org/stable/c/cd830e0bc25ee2d38cbfbdbb3cd77c5f53b2b6d5","https://git.kernel.org/stable/c/ce2d4b121fb7545e1ed588e860c8e5fd5ad45224","https://git.kernel.org/stable/c/68973f9db76144825e4f35dfdc80fb8279eb2d57"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72123","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72123","identifiers":["CVE-2026-72123"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-09T09:04:02.9162191+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-09T09:04:02.9162191+00:00","lastSuccessAt":"2026-11-09T09:04:03.0760313+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:04:03.0760345+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-24e6fde7b744113daefb8f6135035fb8a5c69c9617c9c0d40574a0376532ffd3-0ea295a9c399a04b3ab57ccec2161d0d1cc039ee9ab5c4d8b6299048bd56b277","complete":true,"records":421333,"lastAttemptAt":"2026-11-09T09:02:14.7013141+00:00","lastSuccessAt":"2026-11-09T09:02:14.6291653+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:02:14.7013141+00:00","snapshotPublishedAt":"2026-11-09T08:31:17+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-f975b42a7c2d46f6899c3d764d777217","complete":false,"records":13654,"lastAttemptAt":"2026-11-09T09:16:12.2541949+00:00","lastSuccessAt":"2026-11-09T09:16:12.249+00:00","error":"7 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-09T09:16:12.249+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13699,"expectedIdentifiers":13706,"failedIdentifiers":7},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-09T09:04:02.9162191+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-09T09:04:02.9162191+00:00","lastSuccessAt":"2026-11-09T09:04:03.197028+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:04:03.1970284+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-156d67f0b09643159ff4bd684ee896db","complete":true,"records":13666,"lastAttemptAt":"2026-11-09T09:04:03.6692263+00:00","lastSuccessAt":"2026-11-09T07:04:26.209+00:00","error":null,"lastVerifiedAt":"2026-11-09T07:04:26.209+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-09T09:04:02.7750454+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:04:02.7750454+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-09T09:02:14.7586225+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:02:14.7586225+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-f6d341f4320a5a0c059c28102ee651c3dd06abc87b84d2bafa4e2a823ec07d35","complete":true,"records":3056,"lastAttemptAt":"2026-11-09T09:04:02.8843128+00:00","lastSuccessAt":"2026-11-09T05:02:23.1539412+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:04:02.8843128+00:00","snapshotPublishedAt":"2026-11-09T04:47:48+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-d0592215f99679f1cc533698c7c7cf50c306057d38021110cecb15015dc78137","complete":true,"records":231297,"lastAttemptAt":"2026-11-09T09:04:02.4970329+00:00","lastSuccessAt":"2026-11-09T09:04:00.7848047+00:00","error":null,"lastVerifiedAt":"2026-11-09T09:04:02.4970329+00:00","snapshotPublishedAt":"2026-11-09T08:33:22+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}