CVE-2026-52927netfilter: ebtables: fix OOB read in compat_mtw_from_user
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before d7a8fb6f10d55a1c37b0bf8c20cca24dffd76e00; 81e675c227ec60a0bdcbb547dc530ebee23ff931 builds before 21af4c030567d2e6c89bb927bc18b51fba52a400; from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before dad9ebf8107955bb54bd3f9cf22591b6ff37bac1; from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before a27cb7325a6c69970041c7f8541fafed5a1ea3ec; 81e675c227ec60a0bdcbb547dc530ebee23ff931 builds before 7ad0e463fc7eafae2141cc38054264636f8b3e94; from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before bf8e8eac7ede51dc318e06acef5a896dcbba7595; from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before fcc4c043d137e7f1de4673dba1f3116e45377c67; from 81e675c227ec60a0bdcbb547dc530ebee23ff931 before f438d1786d657d57790c5d138d6db3fc9fdac392 | CNA record |
linux linux_kernel linux:linux_kernel | from 2.6.34 before 5.10.259; from 5.11 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.93; from 6.13 before 6.18.35; from 6.19 before 7.0.12; 7.1; and 4 more ranges | NVD |
References
- https://git.kernel.org/stable/c/d7a8fb6f10d55a1c37b0bf8c20cca24dffd76e00patch
- https://git.kernel.org/stable/c/21af4c030567d2e6c89bb927bc18b51fba52a400patch
- https://git.kernel.org/stable/c/dad9ebf8107955bb54bd3f9cf22591b6ff37bac1patch
- https://git.kernel.org/stable/c/a27cb7325a6c69970041c7f8541fafed5a1ea3ecpatch
- https://git.kernel.org/stable/c/7ad0e463fc7eafae2141cc38054264636f8b3e94patch
- https://git.kernel.org/stable/c/bf8e8eac7ede51dc318e06acef5a896dcbba7595patch
- https://git.kernel.org/stable/c/fcc4c043d137e7f1de4673dba1f3116e45377c67patch
- https://git.kernel.org/stable/c/f438d1786d657d57790c5d138d6db3fc9fdac392patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.