Improper Check or Handling of Exceptional Conditions in Linux kernel - CVE-2026-64264

Vulnerability identifier: #VU139727

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64264

CWE-ID: CWE-703

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause incorrect handling of a failed request.

The vulnerability exists due to improper error handling in fuse_uring_commit when copying an output header from user memory. A local user can trigger a copy_from_user() failure to cause incorrect handling of a failed request.

The positive residual value can be interpreted as success, causing the caller to proceed with an uninitialised or partially populated req->out.args.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/0483fffdeeb363f320e6bf5fc0f0306007507306
• https://git.kernel.org/stable/c/3a0a8bc51a13951c5141262bf770eeea3e0b6228
• https://git.kernel.org/stable/c/fe604c08d874648a69187f6380e5c7858627dc04

• Improper Check or Handling of Exceptional Conditions in Linux kernel fuse
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0