CVE-2026-93240

Summary

In the Linux kernel, the following vulnerability has been resolved:

memcg: make the v1 soft limit knob inert

The v1 soft limit has been deprecated since v6.12 and nobody has reported depending on it. Start the removal by decoupling the interface from the implementation: keep memory.soft_limit_in_bytes, but ignore writes to it and always report the maximum value on read similar to what memory.kmem.limit_in_bytes already does.

Writes are still parsed, so malformed input keeps returning -EINVAL. The knob now also behaves the same everywhere: it used to return -EOPNOTSUPP on PREEMPT_RT, where soft limit reclaim has always been disabled.

This also fixes the syzbot report linked below. Soft limit reclaim is the only caller that runs shrink_lruvec() from kswapd against a specific memcg, so it is the only way to reach lru_gen_shrink_lruvec() and in turn set_mm_walk(), which warns when called from kswapd.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 72fb67f6e0e5d78e4f34cf9929d1afdb0fd54203affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0a90e268cce7023f34087bfa4affb42e29ff5f45affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5ec8f629a300cc40e746d6178f724bdff7683fa7affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a3417097fb107cea3358b19bcbb4eb655fd67f8caffected
LinuxLinux0 < 6.12.110affected
LinuxLinux0 < 6.18.51affected
LinuxLinux0 < 7.2.5affected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.51 <= 6.18.*unaffected
LinuxLinux7.2.5 <= 7.2.*unaffected
LinuxLinux7.3-rc2 <= *unaffected

Weaknesses

References