{"id":"DEBIAN-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":"2026-09-14T17:03:43.867643760Z","published":"2026-07-08T21:16:49.987Z","upstream":["CVE-2026-55206"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-55206"}],"affected":[{"package":{"name":"py7zr","ecosystem":"Debian:12","purl":"pkg:deb/debian/py7zr?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.11.3+dfsg-5","0.11.3+dfsg-6","0.11.3+dfsg-7","0.11.3+dfsg-8","0.21.0+dfsg-1","0.21.0+dfsg-2","0.21.1+dfsg-1","0.22.0+dfsg-1","1.0.0+dfsg1-1","1.0.0+dfsg1-2","1.0.0+dfsg1-3","1.0.0+dfsg1-3~bpo13+1","1.0.0+dfsg1-4","1.0.0+dfsg1-5","1.1.0+dfsg-1~exp1","1.1.2+dfsg-1","1.1.2+dfsg-1~exp1","1.1.2+dfsg-2","1.1.2+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-2","1.1.3+dfsg-1","1.1.3+dfsg-2","1.1.3+dfsg-3","1.1.3+dfsg-4"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55206.json"}},{"package":{"name":"py7zr","ecosystem":"Debian:13","purl":"pkg:deb/debian/py7zr?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.22.0+dfsg-1","1.0.0+dfsg1-1","1.0.0+dfsg1-2","1.0.0+dfsg1-3","1.0.0+dfsg1-3~bpo13+1","1.0.0+dfsg1-4","1.0.0+dfsg1-5","1.1.0+dfsg-1~exp1","1.1.2+dfsg-1","1.1.2+dfsg-1~exp1","1.1.2+dfsg-2","1.1.2+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-2","1.1.3+dfsg-1","1.1.3+dfsg-2","1.1.3+dfsg-3","1.1.3+dfsg-4"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55206.json"}},{"package":{"name":"py7zr","ecosystem":"Debian:14","purl":"pkg:deb/debian/py7zr?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.1.3+dfsg-1"}]}],"versions":["0.22.0+dfsg-1","1.0.0+dfsg1-1","1.0.0+dfsg1-2","1.0.0+dfsg1-3","1.0.0+dfsg1-3~bpo13+1","1.0.0+dfsg1-4","1.0.0+dfsg1-5","1.1.0+dfsg-1~exp1","1.1.2+dfsg-1","1.1.2+dfsg-1~exp1","1.1.2+dfsg-2","1.1.2+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-1","1.1.2-1+really1.1.0+dfsg-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55206.json"}}],"schema_version":"1.9.0","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}