{"id":"CVE-2026-118694","aliases":["DEBIAN-CVE-2026-118694","EUVD-2026-112495","GHSA-rgrp-3mvm-5g9j","UBUNTU-CVE-2026-118694","openSUSE-SU-2026:12422-1"],"status":"published","title":"python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","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":"2026-11-12","score":0.00453,"percentile":0.39816,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-407"],"published":"2026-10-28T21:11:20Z","modified":"2026-11-05T17:27:04Z","fixes":[{"ecosystem":"openSUSE:Tumbleweed","package":"python-markdown2","fixed_in":["2.5.5-3.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.1-1","2.4.11-1","2.5.3-1~exp1","2.5.4-1","2.5.4-2","2.5.4-3","2.5.4-4"]},{"source":"osv","ecosystem":"Debian:13","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.11-1","2.5.3-1~exp1","2.5.4-1","2.5.4-2","2.5.4-3","2.5.4-4"]},{"source":"osv","ecosystem":"Debian:14","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.11-1","2.5.3-1~exp1","2.5.4-1","2.5.4-2","2.5.4-3","2.5.4-4"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.7-2"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.10-1.1","2.4.1-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.1-1","2.4.11-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.4-3"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.11-1","2.5.4-2","2.5.4-3"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"python-markdown2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.5-3.1"}]}]}],"products":[{"vendor":"python-markdown2","product":"python-markdown2"},{"vendor":"trentm","product":"python-markdown2"}],"references":[{"url":"https://github.com/trentm/python-markdown2/issues/750","tags":["issue-tracking","report"]},{"url":"https://github.com/trentm/python-markdown2","tags":["product","package","report"]},{"url":"https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L1478-L1492","tags":["technical-description","article","report"]},{"url":"https://github.com/trentm/python-markdown2/blob/2.5.5/lib/markdown2.py#L3029","tags":["technical-description","article","report"]},{"url":"https://github.com/trentm/python-markdown2/pull/751","tags":["patch","issue-tracking","fix","report"]},{"url":"https://www.vulncheck.com/advisories/python-markdown2-through-2.5.5-denial-of-service-via-unclosed-inline-link-destinations","tags":["third-party-advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118694","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-rgrp-3mvm-5g9j"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/118xxx/CVE-2026-118694.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-118694","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-118694","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-118694","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2026-118694","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2026-118694","title":"python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T21:11:20.814Z","modified":"2026-10-29T17:22:18.429Z","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":"2026-11-02T14:20:03.827373Z"}],"euvd":[{"id":"EUVD-2026-112495","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T21:11:20Z","modified":"2026-10-29T17:22:18Z","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":"2026-11-02T16:59:15.391097Z"}],"ghsa":[{"id":"GHSA-rgrp-3mvm-5g9j","title":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote...","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-29T00:31:24Z","modified":"2026-10-29T00:31:32Z","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":"2026-11-02T15:14:37.567324Z"}],"nvd":[{"id":"CVE-2026-118694","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T22:17:13.7Z","modified":"2026-10-29T18:17:28.427Z","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":"2026-11-02T14:13:04.6346Z"}],"osv":[{"id":"CVE-2026-118694","title":"python-markdown2 through 2.5.5 Denial of Service via Unclosed Inline Link Destinations","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T21:11:20.814Z","modified":"2026-11-05T17:27:04.141748124Z","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"}],"cwes":["CWE-407"],"updated_at":"2026-11-05T17:54:29.515286Z"},{"id":"DEBIAN-CVE-2026-118694","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T22:17:13.7Z","modified":"2026-10-30T10:00:24.008864434Z","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":"2026-11-02T15:45:51.374409Z"},{"id":"UBUNTU-CVE-2026-118694","description":"python-markdown2 through 2.5.5 contains a denial of service vulnerability that allows remote users to exhaust CPU by submitting Markdown with unclosed inline link destinations. Attackers can submit repeated '[a](' or '![a](' sequences, causing _find_balanced to rescan the remaining document for each link and consume quadratic CPU time.","status":"published","published":"2026-10-28T22:17:00Z","modified":"2026-11-05T04:42:51Z","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":"2026-11-05T13:33:25.727744Z"},{"id":"openSUSE-SU-2026:12422-1","title":"python313-markdown2-2.5.5-3.1 on GA media","description":"These are all security issues fixed in the python313-markdown2-2.5.5-3.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-11-04T00:00:00Z","modified":"2026-11-05T17:23:17.519656446Z","updated_at":"2026-11-05T17:55:05.69587Z"}]}}