# CVE-2026-55206: py7zr: py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryp...

CVE-2026-55206 is fixed in 2 products on 1 platform, first by OPENSUSE-SU-2026:21159-1, released June 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-55206
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 25, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | py7zr Debian 14 | 1.1.3+dfsg-1 | [DEBIAN-CVE-2026-55206](https://patchblox.com/security/data/fix/linux/debian-cve-2026-55206.md) | Jul 10, 2026 |
| Linux | python-py7zr opensuse-leap 16.0 | 1.0.0-bp160.2.1 | [OPENSUSE-SU-2026:21159-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21159-1.md) | Jun 25, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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