kcm: use WRITE_ONCE() when changing lower socket callbacks
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: kcm: use WRITE_ONCE() when changing lower socket callbacks kcm_attach() replaces a live lower TCP socket's sk_data_ready and sk_write_space callbacks with KCM handlers, and kcm_unattach() restores them later. Those callback-pointer updates are still plain stores even though the same fields can be read and invoked concurrently on other CPUs. If another CPU observes an older callback snapshot after the live field has already been restored, callback execution can run with a mismatched target and sk_user_data state, leading to stale or misdirected wakeups. Use WRITE_ONCE() for the callback replacement and restore operations so these shared callback fields follow the same visibility contract already established by the earlier 4022 fixes.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74262
- 2026-10-03 Alias added: GHSA-rv7w-h679-g92g
- 2026-10-16 CISA SSVC decision points changed
References
Other 8
- https://git.kernel.org/stable/c/0cb3e2f40679032c1aa2186280a86e5ead0161ee
- https://git.kernel.org/stable/c/fa26e4606aed0f7fe793c325506adeda1d847a43
- https://git.kernel.org/stable/c/b4ccd6eef671d7c44a30123cd29f3acf3de8468e
- https://git.kernel.org/stable/c/b8c90823cdfb5f3d22f261aeb3e9066612853c36
- https://git.kernel.org/stable/c/11faefd11ce2448bac7279ab302dd1954a6547fe
- https://git.kernel.org/stable/c/f01fb6138f8eb606b56ce9158e2d8b72352c53f4
- https://git.kernel.org/stable/c/9684fff87124b201e11dea01ded9173025359a0f
- https://git.kernel.org/stable/c/47186409c092cd7dd70350999186c700233e854d
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Sources
- CVE-2026-74262 · CVE Program
- CVE-2026-74262 · NVD
- FIRST EPSS
- GHSA-rv7w-h679-g92g · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74262 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences