CVE-2026-74262: Linux kernel · kcm: use WRITE_ONCE() when changing lower socket callbacks
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, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% 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 fix is available that applies WRITE_ONCE() to the callback-pointer updates in the Linux kernel's kcm subsystem. Users should update to a patched kernel version where this fix is included.
Description
A concurrency vulnerability in the Linux kernel's kcm subsystem was identified where callback-pointer updates were not properly synchronized across CPUs. This could lead to stale or misdirected wakeups due to improper memory visibility. The issue was fixed by using WRITE_ONCE() to ensure atomic updates and proper synchronization of callback pointers.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74262 (opens in a new tab)
- git.kernel.org/stable/c/0cb3e2f40679032c1aa2186280a86e5ead0161ee (opens in a new tab)
- git.kernel.org/stable/c/11faefd11ce2448bac7279ab302dd1954a6547fe (opens in a new tab)
- git.kernel.org/stable/c/47186409c092cd7dd70350999186c700233e854d (opens in a new tab)
- git.kernel.org/stable/c/9684fff87124b201e11dea01ded9173025359a0f (opens in a new tab)
- git.kernel.org/stable/c/b4ccd6eef671d7c44a30123cd29f3acf3de8468e (opens in a new tab)
- git.kernel.org/stable/c/b8c90823cdfb5f3d22f261aeb3e9066612853c36 (opens in a new tab)
- git.kernel.org/stable/c/f01fb6138f8eb606b56ce9158e2d8b72352c53f4 (opens in a new tab)
- git.kernel.org/stable/c/fa26e4606aed0f7fe793c325506adeda1d847a43 (opens in a new tab)
- ubuntu.com/security/CVE-2026-74262 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74262 (opens in a new tab)
- git.kernel.org/linus/47186409c092cd7dd70350999186c700233e854d (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)