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.
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Affected Vendors & Products
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History
Wed, 08 Jul 2026 21:45:00 +0000
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Miurahr
Miurahr py7zr |
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| Vendors & Products |
Miurahr
Miurahr py7zr |
Wed, 08 Jul 2026 20:45:00 +0000
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| 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. | |
| Title | py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read() | |
| Weaknesses | CWE-407 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-08T20:32:09.905Z
Reserved: 2026-06-16T16:16:32.627Z
Link: CVE-2026-55206
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OpenCVE Enrichment
Updated: 2026-07-08T21:30:08Z