{"id":"CVE-2026-91990","summary":"Tornado before 6.5.8 Memory Amplification DoS via multipart","details":"Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.","aliases":["GHSA-8423-8fgw-73vq"],"modified":"2026-09-17T03:47:21.078177118Z","published":"2026-09-15T15:18:31.715Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91990.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91990.json"},{"type":"ADVISORY","url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91990"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/tornado-before-6.5.8-memory-amplification-dos-via-multipart"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/tornadoweb/tornado","events":[{"introduced":"0"},{"fixed":"a55abe3e3bf59994f29b2f7084c46341f0d4f6a7"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"6.5.8"}],"source":["AFFECTED_FIELD","DESCRIPTION"]}}],"versions":["v6.5.7","v6.5.6","v6.5.5","v6.5.4","v6.5.3","v6.5.2","v6.5.1","v6.5.0","v6.5.0b1","v6.4.1","v6.4.0","v6.4.0b1","v6.3.1","v6.3.0","v6.3.0b1","v6.2.0","v6.2.0b2","v6.2.0b1","v6.1.0","v6.1.0b2","v6.1.0b1","v6.0.0","v6.0.0b1","v5.1.0","v5.0.0","v4.5.0","v4.5.1","v4.4.1","v4.4.0","v4.4.0b1","v4.3.0","v4.3.0b2","v4.3.0b1","v4.2.0","v4.2.0b1","v4.1.0","v4.1.0b2","v4.1.0b1","v4.0.0","v4.0.0b3","v4.0.0b2","v4.0.0b1","v3.2.0","v3.2.0b2","v3.2.0b1","v3.1.0","v3.0.1","v3.0.0","v2.1.1","v2.3.0","v2.2.0","v2.1.0","v2.0.0","v1.2.0","v1.1.0","v1.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-91990.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"}]}