CVE-2026-41991 Details
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
A vulnerability exists in the GNU Gzip utility, specifically within the gzexe command, due to improper management of temporary files. When the mktemp utility is unavailable, gzexe generates temporary file names based solely on the process ID, creating predictable file paths without exclusive access or existence checks. This flaw enables local attackers to pre-create symbolic links pointing to arbitrary writable files. When gzexe is executed, it follows the symlink and overwrites the target file, introducing a time-of-check to time-of-use (TOCTOU) race condition that allows for unauthorized file modifications.
Users can update to the latest version of GNU Gzip, where this vulnerability has been fixed. The patched version is available on the main GNU download server and its mirrors.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 29, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-377 | Insecure Temporary File | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| gnu gzip | <= 1.14 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 1, 2026 | Initial Analysis | [email protected] |
| Jun 29, 2026 | CVE Modified | CISA-ADP |
| Jun 29, 2026 | New CVE Received | [email protected] |