JLSEC-2026-1264 Low 2.0
GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file...
GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite.
This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269
References
- https://cert.pl/en/posts/2026/04/CVE-2026-41991
- https://cert.pl/en/posts/2026/04/CVE-2026-41991/
- https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=4e6f8b24ab823146ab8776f0b7fe486ab34d4269
- https://github.com/advisories/GHSA-67v8-88jf-4x6q
- https://nvd.nist.gov/vuln/detail/CVE-2026-41991
- https://www.gnu.org/software/gzip
- https://www.gnu.org/software/gzip/