CVE-2026-64267: Linux kernel · fuse: avoid 32-bit prune notification count wrap FUSE_NOTIFY_PRUNE validates the
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 7.0.0-1012.12~24.04.1 : update Linux kernel when convenient.
Data as of 9 Nov 2026, 15:49 UTC
- Patch
- Available – fixed in 7.0.0-1012.12~24.04.1, 7.0.0-1014.14~24.04.1, 7.0.0-1013.13~24.04.1 +14
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 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 9 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- 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)
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
A patch is available and should be applied. Fixed kernel versions include 7.0.0-1012.12~24.04.1 and later. Users running affected Linux kernel versions should upgrade to these fixed releases to remediate the vulnerability. No other mitigation or workaround is indicated by the vendor advisory.
Description
CVE-2026-64267 is a vulnerability in the Linux kernel's FUSE subsystem affecting 32-bit kernels. It involves an integer wrap issue in the prune notification count validation, allowing a crafted prune notification to bypass length checks and cause out-of-bounds reads in the userspace write buffer. This can trigger kernel bugs such as fuse_copy_fill() BUG_ON(!err). The flaw is fixed by improving payload length validation to prevent wraparound arithmetic. The vulnerability has a medium severity score and does not impact confidentiality or integrity but can cause denial of service (kernel crash).
References
- ubuntu.com/security/CVE-2026-64267 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64267 (opens in a new tab)
- git.kernel.org/linus/54243797cedf55447b4c5d560e8cd709900061ae (opens in a new tab)
- git.kernel.org/stable/c/54243797cedf55447b4c5d560e8cd709900061ae (opens in a new tab)
- git.kernel.org/stable/c/6e2d84fdeac05bfd858e84a76353fdb84f23a43e (opens in a new tab)
- git.kernel.org/stable/c/c78c4b242299bc581e4987e5c2786c6f4760c516 (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)