high8.7
CVE-2026-55206
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | py7zr | <= 1.1.2 | 1.1.3 |