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VulnerabilityPublished Updated

CVE-2026-63814: Linux kernel · f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 10 Nov 2026, 21:06 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.17.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

What to do

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by adding validation checks in f2fs_acl_from_disk() to ensure ACL entries are properly sized before accessing their fields. Users should update to a Linux kernel version that includes this patch to remediate the issue. Since this is a kernel-level vulnerability, applying the official kernel update is the recommended mitigation. No alternative workarounds are indicated.

Description

CVE-2026-63814 is a high-severity vulnerability in the Linux kernel's f2fs filesystem ACL handling. The flaw involves improper validation of ACL entry sizes in the f2fs_acl_from_disk() function, which can lead to out-of-bounds reads. This occurs because f2fs_acl_count() only checks the aggregate ACL length, allowing malformed ACL entries to cause memory access errors. The issue was identified through a kernel address sanitizer (KASAN) slab-out-of-bounds error. The vulnerability has been resolved by adding stricter validation checks on ACL entry sizes before accessing certain fields.

References

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