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CVE-2026-41991

UNKNOWN 0.0

Predictable Temporary File in GNU gzip

CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th

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

CWE CWE-377
Vendor gnu
Product gzip
Published Jun 29, 2026
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Affected Versions

GNU / gzip
0 ≤ 1.14

References

NVD ↗ CVE.org ↗ EPSS Data ↗
cert.pl: https://cert.pl/en/posts/2026/04/CVE-2026-41991/ gnu.org: https://www.gnu.org/software/gzip/ cgit.git.savannah.gnu.org: https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=4e6f8b24ab823146ab8776f0b7fe486ab34d4269

Credits

Michał Majchrowicz (AFINE) Marcin Wyczechowski (AFINE)