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.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon_linux_2023 | — | Upgrade kernel-modules-extra-commonUpgrade perfUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-toolsUpgrade kernel-tools-develUpgrade bpftoolUpgrade kernelUpgrade python3-perfUpgrade kernel-livepatch-6.1.180-225.360Upgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-modules-extraUpgrade perf-debuginfoUpgrade kernel-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-headersUpgrade kernel-develUpgrade python3-perf-debuginfo | Sep 1, 2026 | Aug 15, 2026 |
| Debian | — | Upgrade linux | Aug 16, 2026 | Aug 16, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Aug 21, 2026 | Aug 15, 2026 |
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