{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-72123", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-72123", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-08-15T05:53:01.433Z", "updatedAt": "2026-10-16T18:44:57.598Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "can: bcm: defer rx_op deallocation to workqueue to fix thrtimer UAF", "summary": "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.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "85cd41070df992d3c0dfd828866fdd243d3b774a", "status": "affected", "versionType": "git", "lessThan": "de5fce46637de05bef56ec08528127676eb6fc9b" }, { "version": "f34f2a18e47b73e48f90a757e1f4aaa8c7d665a1", "status": "affected", "versionType": "git", "lessThan": "036a8c320ca11bc912e8027adcfad14b326f067e" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "3cf4fd5316f449811d8baf1bc6978ef5a7b743a9" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "4177762f70646ac48a2af382e45a795cbd295198" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "6fd08e8d826c3aa4cc7021f5f9cdbb7fa7441d3f" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "cd830e0bc25ee2d38cbfbdbb3cd77c5f53b2b6d5" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "ce2d4b121fb7545e1ed588e860c8e5fd5ad45224" }, { "version": "f1b4e32aca0811aa011c76e5d6cf2fa19224b386", "status": "affected", "versionType": "git", "lessThan": "68973f9db76144825e4f35dfdc80fb8279eb2d57" }, { "version": "fbac09a3b8890003c0c55294c00709f3ae5501bb", "status": "affected", "versionType": "git" }, { "version": "5b48f5711f1c630841ab78dcc061de902f0e37bf", "status": "affected", "versionType": "git" }, { "version": "edb4baffb9483141a50fb7f7146cfe4a4c0c2db8", "status": "affected", "versionType": "git" }, { "version": "5.10.130", "status": "affected", "versionType": "semver", "lessThan": "5.10.265" }, { "version": "5.15.54", "status": "affected", "versionType": "semver", "lessThan": "5.15.216" }, { "version": "4.19.252", "status": "affected", "versionType": "semver", "lessThan": "4.20" }, { "version": "5.4.205", "status": "affected", "versionType": "semver", "lessThan": "5.5" }, { "version": "5.18.11", "status": "affected", "versionType": "semver", "lessThan": "5.19" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.19" }, { "version": "5.10.265", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.216", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.178", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.145", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.97", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.40", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.5", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }