Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-46159
Published: May 29, 2026
Vulnerability identifier: #VU133035
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-46159
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to a time-of-check time-of-use race in btrfs_ioctl_space_info() when processing a space information ioctl request while block groups are concurrently removed. A local user can trigger the ioctl and race concurrent block group removal to disclose sensitive information.
The issue can result in copying uninitialized kmalloc heap bytes to userspace.
How to mitigate CVE-2026-46159
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3
- https://git.kernel.org/stable/c/5d12e0ab009ade48c1bff9324fd9bea2c773d088
- https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77
- https://git.kernel.org/stable/c/d09d67d5de577cedae3de9497dff217e0ac8b641
- https://git.kernel.org/stable/c/f5ee467b56764964027c361641f64953fc0f8f9a