uutils coreutils split Arbitrary File Truncation via Time-of-Check to Time-of-Use (TOCTOU) Race Condition

A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in the split utility of uutils coreutils. The program attempts to prevent data loss by checking for identity between input and output files using their file paths before initiating the split operation. However, the utility subsequently opens the output file with truncation after this path-based validation is complete. A local attacker with write access to the directory can exploit this race window by manipulating mutable path components (e.g., swapping a path with a symbolic link). This can cause split to truncate and write to an unintended target file, potentially including the input file itself or other sensitive files accessible to the process, leading to permanent data loss.

Source published

22 Apr 2026 16:09:04 UTC

Source modified

22 Apr 2026 17:19:14 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H