CVE-2026-72123: Linux kernel · can: bcm: defer rx_op deallocation to workqueue to fix thrtimer UAF
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +42
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and should be applied to affected Linux kernel versions. The fix defers timer cancellation and memory deallocation to a dedicated workqueue to safely handle the use-after-free condition. Users should update to patched kernel versions as provided by their Linux distribution vendors. No additional mitigation steps are indicated beyond applying the official fix.
Description
A use-after-free (UAF) vulnerability was resolved in the Linux kernel's CAN BCM driver related to deferred deallocation of rx_op structures. The issue involved a race condition where a timer callback could access freed memory, causing potential system instability or compromise. The fix defers timer cancellation and memory deallocation to a dedicated workqueue to avoid unsafe operations in atomic context and prevent use-after-free conditions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72123 (opens in a new tab)
- git.kernel.org/stable/c/3cf4fd5316f449811d8baf1bc6978ef5a7b743a9 (opens in a new tab)
- git.kernel.org/stable/c/4177762f70646ac48a2af382e45a795cbd295198 (opens in a new tab)
- git.kernel.org/stable/c/68973f9db76144825e4f35dfdc80fb8279eb2d57 (opens in a new tab)
- git.kernel.org/stable/c/6fd08e8d826c3aa4cc7021f5f9cdbb7fa7441d3f (opens in a new tab)
- git.kernel.org/stable/c/cd830e0bc25ee2d38cbfbdbb3cd77c5f53b2b6d5 (opens in a new tab)
- git.kernel.org/stable/c/ce2d4b121fb7545e1ed588e860c8e5fd5ad45224 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72123 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72123 (opens in a new tab)
- git.kernel.org/linus/68973f9db76144825e4f35dfdc80fb8279eb2d57 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-2 (opens in a new tab)