{"id":"DEBIAN-CVE-2026-82397","details":"Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.8, Tornado parses application/x-www-form-urlencoded request bodies with urllib.parse.parse_qs in tornado/escape.py without passing max_num_fields. RequestHandler._execute in tornado/web.py parses the body before handler dispatch through HTTPServerRequest._parse_body and parse_body_arguments in tornado/httputil.py, so an unauthenticated request body containing millions of separator-delimited fields can synchronously stall the single-threaded event loop and delay every connection. The body is bounded only by max_buffer_size, which defaults to 104857600 bytes. This issue is fixed in version 6.5.8.","modified":"2026-09-10T08:47:25.248671525Z","published":"2026-08-31T22:17:22.920Z","upstream":["CVE-2026-82397"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-82397"}],"affected":[{"package":{"name":"python-tornado","ecosystem":"Debian:12","purl":"pkg:deb/debian/python-tornado?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.2.0-3","6.2.0-3+deb12u1","6.2.0-3+deb12u2","6.2.0-3+deb12u3","6.2.0-3+deb12u4","6.3.2-1","6.4.0-1","6.4.0-2","6.4.1-1","6.4.1-2","6.4.1-3","6.4.2-1","6.4.2-2","6.4.2-3","6.5.2-1","6.5.2-2","6.5.2-3","6.5.4-0.1","6.5.4-1","6.5.5-1","6.5.5-2","6.5.5-3","6.5.5-4","6.5.5-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-82397.json"}},{"package":{"name":"python-tornado","ecosystem":"Debian:13","purl":"pkg:deb/debian/python-tornado?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.4.2-3","6.4.2-3+deb13u1","6.4.2-3+deb13u2","6.5.2-1","6.5.2-2","6.5.2-3","6.5.4-0.1","6.5.4-1","6.5.5-1","6.5.5-2","6.5.5-3","6.5.5-4","6.5.5-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-82397.json"}},{"package":{"name":"python-tornado","ecosystem":"Debian:14","purl":"pkg:deb/debian/python-tornado?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.4.2-3","6.5.2-1","6.5.2-2","6.5.2-3","6.5.4-0.1","6.5.4-1","6.5.5-1","6.5.5-2","6.5.5-3","6.5.5-4","6.5.5-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-82397.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}