{"id":"CVE-2026-55206","state":"PUBLISHED","title":"py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()","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.","publishedAt":"2026-07-08T20:32:09.905Z","updatedAt":"2026-07-09T14:26:55.698Z","severity":{"score":8.7,"label":"High","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["miurahr py7zr"],"affected":[{"vendor":"miurahr","product":"py7zr","versions":[{"version":"< 1.1.3","status":"affected"}]}],"references":["https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8","https://github.com/miurahr/py7zr/releases/tag/v1.1.3"],"weaknesses":["CWE-407"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55206.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55206","state":"PUBLISHED","datePublished":"2026-07-08T20:32:09.905Z","dateUpdated":"2026-07-09T14:26:55.698Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T16:16:32.627Z"},"containers":{"cna":{"title":"py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"miurahr","product":"py7zr","versions":[{"version":"< 1.1.3","status":"affected"}]}],"references":[{"url":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","name":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8","name":"https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8","tags":["x_refsource_MISC"]},{"url":"https://github.com/miurahr/py7zr/releases/tag/v1.1.3","name":"https://github.com/miurahr/py7zr/releases/tag/v1.1.3","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-407","lang":"en","description":"CWE-407: Inefficient Algorithmic Complexity","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-08T20:32:09.905Z"},"source":{"advisory":"GHSA-h4gh-22qq-72r7","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-09T14:26:52.381780Z","id":"CVE-2026-55206","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-09T14:26:55.698Z"}}]}}}