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 · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +43
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
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official patch is available and should be applied to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this vulnerability has been fixed in updated kernel packages. Users should update their Linux kernel to the fixed versions as provided by their distribution. No additional mitigation is required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's f2fs filesystem ACL handling was resolved. The issue involved improper validation of ACL entry sizes, allowing malformed ACLs to cause out-of-bounds reads. This could lead to memory corruption and potentially escalate privileges or cause denial of service. The flaw was fixed by adding stricter validation checks on ACL entries to prevent reading beyond allocated memory. The vulnerability has a CVSS score of 7.8, indicating a high impact on confidentiality, integrity, and availability. Multiple Linux kernel versions are affected, and patches are available.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63814 (opens in a new tab)
- git.kernel.org/stable/c/1ddf3fd21c4c652f9cab5552515c04a166662306 (opens in a new tab)
- git.kernel.org/stable/c/442ca20c54038e2400cf28aaa944cf1de2c8e65d (opens in a new tab)
- git.kernel.org/stable/c/4e2a96ec7236e248e706850568e0a925fd21b588 (opens in a new tab)
- git.kernel.org/stable/c/5d8a39649947a4e86c8fbc682d7fc0041b8d109a (opens in a new tab)
- git.kernel.org/stable/c/733cd8474e6d763d75ed96f3f2b98a25480cf2b9 (opens in a new tab)
- git.kernel.org/stable/c/aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1 (opens in a new tab)
- git.kernel.org/stable/c/c4810ada31e80cbe4011467c4f3b1e93f94134f3 (opens in a new tab)
- git.kernel.org/stable/c/ff83de56882cb8466184d322abece2589258ca56 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63814 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63814 (opens in a new tab)
- git.kernel.org/linus/c4810ada31e80cbe4011467c4f3b1e93f94134f3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)