CVE-2026-74262
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk4th percentile - higher than 4% of all known CVEs
Summary
In the Linux kernel, the KCM module's kcm_attach() and kcm_unattach() functions replace callback pointers (sk_data_ready, sk_write_space) on a live TCP socket without using WRITE_ONCE(). This can lead to inconsistent observations of these fields on other CPUs and incorrect callback invocations.
Risk Assessment
Inconsistent updates of callback pointers can cause incorrect process wakeups or misdirected traffic, potentially leading to application malfunctions or man-in-the-middle attacks.
Recommendation
Apply the Linux kernel patch that uses WRITE_ONCE() when replacing and restoring callback pointers in KCM.
Original NVD description (English source)
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.