CVE-2026-72121: Linux kernel · can: bcm: add locking when updating filter and timer values
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 28% 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:A/AC:L/PR:N/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 to address this concurrency vulnerability. The fix introduces proper locking mechanisms to prevent simultaneous access issues. Users should update to patched kernel versions as listed in the advisory. No additional mitigation is required beyond applying the official fix.
Description
A race condition vulnerability in the Linux kernel's CAN BCM subsystem was resolved by adding proper locking when updating filter and timer values. The flaw involved simultaneous access to timer and filter data structures that could be overwritten during concurrent operations, potentially leading to inconsistent or stale CAN frame transmissions. The fix introduces a per-operation lock to protect these updates and ensures atomic consistency of frame data. The vulnerability affects specific Linux kernel versions and has a high CVSS score indicating significant confidentiality, integrity, and availability impact.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72121 (opens in a new tab)
- git.kernel.org/stable/c/19b1994069dd29478ba767de1f98f14a088198dc (opens in a new tab)
- git.kernel.org/stable/c/749179c2e25b95d22499ed29096b3e02d6dfd2b4 (opens in a new tab)
- git.kernel.org/stable/c/834cbca3b12e46887f7a9b35f1981a888360ea4c (opens in a new tab)
- git.kernel.org/stable/c/a7eb6db1cd3f7b556a301dc1265945ad112089f7 (opens in a new tab)
- git.kernel.org/stable/c/fc9f5ee1b073bd233d9c604e338af4ebb42cbc33 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72121 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72121 (opens in a new tab)
- git.kernel.org/linus/749179c2e25b95d22499ed29096b3e02d6dfd2b4 (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)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)