{"cve":"CVE-2026-55206","nvd":{"published":"2026-07-08T21:16:49.987","modified":"2026-10-25T17:10:00.197","status":"Deferred","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.","cvss_v4":{"vector":"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","score":8.7},"cvss_v3":null,"cwes":["CWE-407"],"references":["https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8","https://github.com/miurahr/py7zr/releases/tag/v1.1.3","https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-55206","score":0.00321,"percentile":0.24853,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-h4gh-22qq-72r7","url":"https://osv.dev/vulnerability/GHSA-h4gh-22qq-72r7","summary":"py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()","modified":"2026-07-13T16:43:06.899048591Z","packages":[{"ecosystem":"PyPI","name":"py7zr","purl":"pkg:pypi/py7zr","ranges":["<1.1.3"],"fixed":["1.1.3"]}]},{"id":"PYSEC-2026-2973","url":"https://osv.dev/vulnerability/PYSEC-2026-2973","summary":"py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()","modified":"2026-07-13T16:32:08.005149350Z","packages":[{"ecosystem":"PyPI","name":"py7zr","purl":"pkg:pypi/py7zr","ranges":["<1.1.3"],"fixed":["1.1.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}