CVE-2026-63814: Linux kernel · f2fs: validate ACL entry sizes in f2fs_acl_from_disk()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 10 Nov 2026, 21:06 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 7.8 |
|---|
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
- git.kernel.org/stable/c/733cd8474e6d763d75ed96f3f2b98a25480cf2b9 (opens in a new tab)
- git.kernel.org/stable/c/4e2a96ec7236e248e706850568e0a925fd21b588 (opens in a new tab)
- git.kernel.org/stable/c/442ca20c54038e2400cf28aaa944cf1de2c8e65d (opens in a new tab)
- git.kernel.org/stable/c/1ddf3fd21c4c652f9cab5552515c04a166662306 (opens in a new tab)
- git.kernel.org/stable/c/aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1 (opens in a new tab)
- git.kernel.org/stable/c/ff83de56882cb8466184d322abece2589258ca56 (opens in a new tab)
- git.kernel.org/stable/c/5d8a39649947a4e86c8fbc682d7fc0041b8d109a (opens in a new tab)
- git.kernel.org/stable/c/c4810ada31e80cbe4011467c4f3b1e93f94134f3 (opens in a new tab)