netfilter: ebtables: fix OOB read in compat_mtw_from_user (Linux Linux)

CVE-2026-52927
HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.12 % · percentile 2 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

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.

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < d7a8fb6f10d55a1c37b0bf8c20cca24dffd76e00 ; affected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < 21af4c030567d2e6c89bb927bc18b51fba52a400 ; affected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < dad9ebf8107955bb54bd3f9cf22591b6ff37bac1 ; affected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < a27cb7325a6c69970041c7f8541fafed5a1ea3ec ; affected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < 7ad0e463fc7eafae2141cc38054264636f8b3e94 ; affected 81e675c227ec60a0bdcbb547dc530ebee23ff931 < bf8e8eac7ede51dc318e06acef5a896dcbba7595
Linux · Linuxaffected 2.6.34 ; unaffected 0 < 2.6.34 ; unaffected 5.10.259 ≤ 5.10.* ; unaffected 5.15.210 ≤ 5.15.* ; unaffected 6.1.176 ≤ 6.1.* ; unaffected 6.6.143 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD