{"id":"CVE-2019-25781","aliases":["AZL-112457","AZL-112517","DEBIAN-CVE-2019-25781","EUVD-2019-20211","GHSA-4g9h-pv2v-fw83","UBUNTU-CVE-2019-25781"],"status":"published","title":"Python-Markdown 3.0 through 3.11.2 Denial of Service via Link Bracket Parsing","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","severity":{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00422,"percentile":0.36807,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-407"],"published":"2026-10-29T13:08:49Z","modified":"2026-11-04T10:00:04Z","affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"3.8.2-3"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"tensorflow","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.16.1-11"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10-1","3.10-2","3.10.1-1","3.10.2-1","3.10.2-2","3.10.3-1","3.11.2-1","3.4.1-2","3.4.1-2+deb12u1","3.4.3-1","3.4.4-1","3.5.2-1","3.6-1","3.7-1","3.7-2","3.8.2-1","3.8.2-2","3.9-1"]},{"source":"osv","ecosystem":"Debian:13","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10-1","3.10-2","3.10.1-1","3.10.2-1","3.10.2-2","3.10.3-1","3.11.2-1","3.7-2","3.7-2+deb13u1","3.8.2-1","3.8.2-2","3.9-1"]},{"source":"osv","ecosystem":"Debian:14","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10-1","3.10-2","3.10.1-1","3.10.2-1","3.10.2-2","3.10.3-1","3.11.2-1","3.7-2","3.8.2-1","3.8.2-2","3.9-1"]},{"source":"osv","ecosystem":"Ubuntu:14.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.1-1","2.3.1-2","2.4-1","2.4-1ubuntu0.14.04.1"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.2-1","2.6.3-1","2.6.4-1","2.6.5-1","2.6.5-2","2.6.6-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.6.9-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.1-2","3.1.1-2build1","3.1.1-3"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.4-1","3.3.6-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.4-1","3.5.2-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10.2-1","3.10.2-2","3.10.3-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"python-markdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.8.2-2","3.10-1","3.10-2","3.10.2-1"]}],"products":[{"vendor":"gomarkdown","product":"markdown"},{"vendor":"python-markdown","product":"markdown"}],"references":[{"url":"https://github.com/Python-Markdown/markdown/issues/798","tags":["issue-tracking","report"]},{"url":"https://github.com/Python-Markdown/markdown","tags":["product","package","report"]},{"url":"https://github.com/Python-Markdown/markdown/issues/1654","tags":["issue-tracking","exploit","report"]},{"url":"https://github.com/Python-Markdown/markdown/blob/b41e0aaf1181f1a8cb200cf5a815aad7c0020d23/markdown/inlinepatterns.py#L1155-L1172","tags":["technical-description","web","report"]},{"url":"https://www.vulncheck.com/advisories/python-markdown-3.0-through-3.11.2-denial-of-service-via-link-bracket-parsing","tags":["third-party-advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2019-25781","tags":["web"]},{"url":"https://github.com/advisories/GHSA-4g9h-pv2v-fw83"},{"url":"https://security-tracker.debian.org/tracker/CVE-2019-25781","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2019-25781","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2019-25781","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2019-25781","title":"Python-Markdown 3.0 through 3.11.2 Denial of Service via Link Bracket Parsing","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T13:08:49.597Z","modified":"2026-11-03T15:29:33.399Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-407"],"updated_at":"2026-11-03T16:58:09.635057Z"}],"euvd":[{"id":"EUVD-2019-20211","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T13:08:49Z","modified":"2026-11-03T15:29:33Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-03T16:18:15.107036Z"}],"ghsa":[{"id":"GHSA-4g9h-pv2v-fw83","title":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline...","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T15:30:51Z","modified":"2026-10-29T15:30:51Z","cvss":[{"version":"4.0","score":8.7,"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/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","level":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-407"],"updated_at":"2026-11-02T15:14:38.729227Z"}],"nvd":[{"id":"CVE-2019-25781","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:39.17Z","modified":"2026-11-03T16:17:15.607Z","cvss":[{"version":"4.0","score":8.7,"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/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","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-407"],"updated_at":"2026-11-03T18:16:46.837221Z"}],"osv":[{"id":"CVE-2019-25781","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:39.17Z","modified":"2026-11-05T03:28:37.395222958Z","cvss":[{"version":"4.0","score":8.7,"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/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","level":"high"}],"updated_at":"2026-11-05T07:12:48.26887Z"},{"id":"DEBIAN-CVE-2019-25781","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:39.17Z","modified":"2026-11-04T10:00:04.146647879Z","cvss":[{"version":"4.0","score":8.7,"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/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","level":"high"}],"updated_at":"2026-11-04T10:05:32.187009Z"},{"id":"UBUNTU-CVE-2019-25781","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:00Z","modified":"2026-11-05T04:02:30Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-05T13:33:42.748455Z"},{"id":"AZL-112457","title":"CVE-2019-25781 affecting package python-markdown 3.8.2-3","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:39Z","modified":"2026-11-05T05:40:51Z","updated_at":"2026-11-05T16:41:19.001909Z"},{"id":"AZL-112517","title":"CVE-2019-25781 affecting package tensorflow 2.16.1-11","description":"Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.","status":"published","published":"2026-10-29T14:17:39Z","modified":"2026-11-03T05:33:06Z","updated_at":"2026-11-05T16:41:19.001909Z"}]}}