CVE-2026-35355 PUBLISHED

uutils coreutils install Arbitrary File Overwrite via Symlink TOCTOU Race

Assigner: canonical
Reserved: 02.04.2026 Published: 22.04.2026 Updated: 22.04.2026

The install utility in uutils coreutils is vulnerable to a Time-of-Check to Time-of-Use (TOCTOU) race condition during file installation. The implementation unlinks an existing destination file and then recreates it using a path-based operation without the O_EXCL flag. A local attacker can exploit the window between the unlink and the subsequent creation to swap the path with a symbolic link, allowing them to redirect privileged writes to overwrite arbitrary system files.

Metrics

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

Product Status

Vendor Uutils
Product coreutils
Versions Default: unaffected
  • affected from 0 to 0.6.0 (excl.)

Credits

  • Zellic finder

References

Problem Types

  • CWE-367: Time-of-Check Time-of-Use (TOCTOU) Race Condition CWE

Impacts

  • CAPEC-29: Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions