# CVE-2026-41991

## Summary

- **CVE ID:** CVE-2026-41991
- **Severity:** LOW
- **CVSS Score:** 2 (CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-377
- **Published:** Jun 29, 2026
- **Last Modified:** Sep 14, 2026

## 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

## Affected Products

- GNU — gzip (0)

## References

- [CNA](https://cert.pl/en/posts/2026/04/CVE-2026-41991/)
- [CNA](https://www.gnu.org/software/gzip/)
- [CNA](https://cgit.git.savannah.gnu.org/cgit/gzip.git/commit/?id=4e6f8b24ab823146ab8776f0b7fe486ab34d4269)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.19%
- **EPSS Percentile:** 8.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._