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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-41991

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling.

LOW 2.0EPSS 0.12%

Does this matter?

Lower severity and a low EPSS score (0.12%). Track it; it rarely justifies an emergency change on its own.

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 4.0
2.0 LOWCVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.12% probability · 2th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-377
Affected
gnu/gzip
Source
cvd@cert.pl
EPSS trend
0%3%5%26 October 2026: 0.12%26 October 202626 October 2026

EPSS 0.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.