VDB
CVE-2026-55206
CVE-2026-55206
PUBLISHED
CVSS 8.7 HIGH
Reported by GitHub_M · Published July 8, 2026
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3.
Risk Scores
CVSS 4.0
8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| miurahr | py7zr | < 1.1.3 |
| miurahr | py7zr | < 1.1.3, < 1.1.3, < 1.1.3 |
| PyPI | py7zr | 0 |
Timeline
- Jun 19, 2026 CVE Published
- Jul 9, 2026 Coalition ESS Score
- Jul 9, 2026 Security Advisory
- Aug 7, 2026 EPSS Score
- Aug 24, 2026 EPSS Score
- Aug 27, 2026 EPSS Score
- Sep 1, 2026 EPSS Score
- Sep 6, 2026 EPSS Score
References
- https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7 x_refsource_CONFIRM
- https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8 x_refsource_MISC
- https://github.com/miurahr/py7zr/releases/tag/v1.1.3 x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-55206 advisory
- https://github.com/advisories/GHSA-h4gh-22qq-72r7 advisory