CVE-2026-52927
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: fix OOB read in compat_mtw_from_user Luxiao Xu says: The function compat_mtw_from_user() converts ebtables extensions from 32-bit user structures to kernel native structures. However, it lacks proper validation of the user-supplied match_size/target_size. When certain extensions are processed, the kernel-side translation logic may perform memory accesses based on the extension's expected size. If the user provides a size smaller than what the extension requires, it results in an out-of-bounds read as reported by KASAN. This fix introduces a check to ensure match_size is at least as large as the extension's required compatsize. This covers matches, watchers, and targets, while maintaining compatibility with standard targets. AFAIU this is relevant for matches that need to go though match->compat_from_user() call. Those that use plain memcpy with the user-provided size are ok because the caller checks that size vs the start of the next rule entry offset (which itself is checked vs. total size copied from userspace). The ->compat_from_user() callbacks assume they can read compatsize bytes, so they need this extra check. Based on an earlier patch from Luxiao Xu.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://git.kernel.org/stable/c/21af4c030567d2e6c89bb927bc18b51fba52a400
- https://git.kernel.org/stable/c/7ad0e463fc7eafae2141cc38054264636f8b3e94
- https://git.kernel.org/stable/c/a27cb7325a6c69970041c7f8541fafed5a1ea3ec
- https://git.kernel.org/stable/c/bf8e8eac7ede51dc318e06acef5a896dcbba7595
- https://git.kernel.org/stable/c/d7a8fb6f10d55a1c37b0bf8c20cca24dffd76e00
- https://git.kernel.org/stable/c/dad9ebf8107955bb54bd3f9cf22591b6ff37bac1
- https://git.kernel.org/stable/c/f438d1786d657d57790c5d138d6db3fc9fdac392
- https://git.kernel.org/stable/c/fcc4c043d137e7f1de4673dba1f3116e45377c67
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.