Vulnerability Description
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
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Gnu | Gzip | <= 1.14 |
Related Weaknesses (CWE)
References
- https://cert.pl/en/posts/2026/04/CVE-2026-41991/Broken Link
- https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=4e6f8b24ab823146ab877Patch
- https://www.gnu.org/software/gzip/Product
FAQ
What is CVE-2026-41991?
CVE-2026-41991 is a vulnerability with a CVSS score of 4.7 (MEDIUM). 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 temp...
How severe is CVE-2026-41991?
CVE-2026-41991 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-41991?
Check the references section above for vendor advisories and patch information. Affected products include: Gnu Gzip.