CVE-2026-41991
Publication date 29 June 2026
Last updated 23 September 2026
Ubuntu priority
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
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| gzip | 26.04 LTS resolute |
Fixed in 1.14-1~exp2ubuntu1.1
|
| 24.04 LTS noble |
Fixed in 1.12-1ubuntu3.2
|
|
| 22.04 LTS jammy |
Fixed in 1.10-4ubuntu4.2
|
|
| 20.04 LTS focal |
Fixed in 1.10-0ubuntu4.1+esm1
|
|
| 18.04 LTS bionic |
Fixed in 1.6-5ubuntu1.2+esm1
|
|
| 16.04 LTS xenial |
Fixed in 1.6-4ubuntu1+esm2
|
|
| 14.04 LTS trusty |
Fixed in 1.6-3ubuntu1+esm2
|
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CVSS version:
Base score
2.0 · Low
Vector: 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
Base score
4.7 · Medium
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
References
Related Ubuntu Security Notices (USN)
- USN-8512-1
- Gzip vulnerabilities
- 6 July 2026
- USN-8733-1
- Gzip vulnerabilities
- 7 September 2026
- USN-8733-2
- Gzip vulnerabilities
- 22 September 2026