Algorithmic Complexity Affecting py7zr package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.27% (19th percentile)

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  • Snyk IDSNYK-DEBIAN13-PY7ZR-17938568
  • published10 Jul 2026
  • disclosed8 Jul 2026

Introduced: 8 Jul 2026

CVE-2026-55206  (opens in a new tab)
CWE-407  (opens in a new tab)

How to fix?

There is no fixed version for Debian:13 py7zr.

NVD Description

Note: Versions mentioned in the description apply only to the upstream py7zr package and not the py7zr package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

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.