{"id":"UBUNTU-CVE-2026-55206","details":"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.","modified":"2026-07-15T17:53:44Z","published":"2026-07-08T21:16:00Z","upstream":["CVE-2026-55206"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55206"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55206"},{"type":"REPORT","url":"https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8"},{"type":"REPORT","url":"https://github.com/miurahr/py7zr/releases/tag/v1.1.3"},{"type":"REPORT","url":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}],"affected":[{"package":{"name":"py7zr","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/py7zr?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.11.3+dfsg-1","0.11.3+dfsg-1ubuntu1","0.11.3+dfsg-2","0.11.3+dfsg-3","0.11.3+dfsg-4","0.11.3+dfsg-4ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-py7zr","binary_version":"0.11.3+dfsg-4ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55206.json"}},{"package":{"name":"py7zr","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/py7zr?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.11.3+dfsg-6","0.11.3+dfsg-7","0.11.3+dfsg-8","0.11.3+dfsg-8build1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-py7zr","binary_version":"0.11.3+dfsg-8build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55206.json"}},{"package":{"name":"py7zr","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/py7zr?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.22.0+dfsg-1","1.0.0+dfsg1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-py7zr","binary_version":"1.0.0+dfsg1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55206.json"}},{"package":{"name":"py7zr","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/py7zr?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.0+dfsg1-1","1.0.0+dfsg1-3","1.0.0+dfsg1-4","1.0.0+dfsg1-5","1.1.2+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.1.2+dfsg-1","binary_name":"python3-py7zr"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55206.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}