UBUNTU-CVE-2026-35354: Medium severity ubuntu/rust-coreutils vulnerability
A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in the mv utility of uutils coreutils during cross-device moves. The extended attribute (xattr) preservation logic uses multiple path-based system calls that perform fresh path-to-inode lookups for each operation. A local attacker with write access to the directory can exploit this race to swap files between calls, causing the destination file to receive an inconsistent mix of security xattrs, such as SELinux labels or file capabilities.
Affected Software
Event History
Frequently Asked Questions
What level of access is required to exploit this issue?
An attacker needs local access and write permission to the directory involved in the move operation. Exploitation also requires winning a race by swapping files while mv performs its xattr-preservation operations.
When is the vulnerable code path used?
The issue affects cross-device moves, where mv must preserve extended attributes while moving a file between filesystems or devices. The race arises because those xattr operations use separate path-based lookups.
What is the likely security impact if exploitation succeeds?
The destination file can receive an inconsistent combination of security-related extended attributes. Examples include SELinux labels and file capabilities, potentially affecting the destination file's integrity.