USN-8733-1: Gzip vulnerabilities
Ubuntu issued USN-8733-1 fixing two Gzip flaws: insecure gzexe temp files allowing file overwrites, and a crafted-file DoS/info exposure bug.
USN-8733-1 updates Gzip in Ubuntu to fix CVE-2026-41991, where the gzexe utility created temporary files insecurely when mktemp was unavailable, letting a local attacker overwrite arbitrary files. It also fixes CVE-2026-41992, incorrect handling of certain compressed files that could expose sensitive information or crash Gzip in a denial of service. Both issues have local impact and are addressed via updated Ubuntu packages.
- CVE-2026-41991: insecure temporary file handling in gzexe allows local arbitrary file overwrite
- CVE-2026-41992: crafted compressed files can cause information exposure or denial of service
- Both flaws are local-impact; users should install updated Gzip packages
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2026-41992 +1 in the same advisory: …41991 | GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decomp GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d. NVD description · AI analysis pending | 6.9 group max | <1% |
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Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip's gzexe utility created temporary files in an insecure manner when mktemp was unavailable. A local attacker could possibly use this issue to overwrite arbitrary files. (CVE-2026-41991) Elias Hasas, Michał Majchrowicz and Marcin Wyczechowski discovered that Gzip incorrectly handled certain compressed files. An attacker could possibly use this issue to obtain sensitive information or cause Gzip to crash, resulting in a denial of service. (CVE-2026-41992)
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