{"id":"CVE-2026-83606","state":"PUBLISHED","title":"xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions","description":"xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0-beta.9 until 0.9.11, the processing-instruction production in lib/grammar.js lets the greedy S+ separator and lazy Char*? data group repeatedly repartition a long whitespace tail when the required closing ?> is absent. Both parsePI and parseProcessingInstruction apply the expression to the entire remaining source, causing quadratic backtracking during DOMParser.parseFromString() under default options and allowing a small unauthenticated XML input to stall the Node.js event loop. This issue is fixed in @xmldom/xmldom version 0.9.11.","publishedAt":"2026-09-01T14:21:27.215Z","updatedAt":"2026-09-01T14:57:43.875Z","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":["xmldom xmldom","@xmldom xmldom"],"affected":[{"vendor":"xmldom","product":"xmldom","versions":[{"version":">= 0.9.0-beta.9, < 0.9.11","status":"affected"}]},{"vendor":"@xmldom","product":"xmldom","versions":[{"version":">= 0.9.0-beta.9, < 0.9.11","status":"affected"}]}],"references":["https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7","https://github.com/xmldom/xmldom/pull/1039","https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e","https://github.com/xmldom/xmldom/releases/tag/0.9.11"],"weaknesses":["CWE-400","CWE-1333"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/83xxx/CVE-2026-83606.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-83606","state":"PUBLISHED","datePublished":"2026-09-01T14:21:27.215Z","dateUpdated":"2026-09-01T14:57:43.875Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-31T20:36:25.743Z"},"containers":{"cna":{"title":"xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions","descriptions":[{"lang":"en","value":"xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. From 0.9.0-beta.9 until 0.9.11, the processing-instruction production in lib/grammar.js lets the greedy S+ separator and lazy Char*? data group repeatedly repartition a long whitespace tail when the required closing ?> is absent. Both parsePI and parseProcessingInstruction apply the expression to the entire remaining source, causing quadratic backtracking during DOMParser.parseFromString() under default options and allowing a small unauthenticated XML input to stall the Node.js event loop. This issue is fixed in @xmldom/xmldom version 0.9.11."}],"affected":[{"vendor":"xmldom","product":"xmldom","versions":[{"version":">= 0.9.0-beta.9, < 0.9.11","status":"affected"}]},{"vendor":"@xmldom","product":"xmldom","versions":[{"version":">= 0.9.0-beta.9, < 0.9.11","status":"affected"}]}],"references":[{"url":"https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7","name":"https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/xmldom/xmldom/pull/1039","name":"https://github.com/xmldom/xmldom/pull/1039","tags":["x_refsource_MISC"]},{"url":"https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e","name":"https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e","tags":["x_refsource_MISC"]},{"url":"https://github.com/xmldom/xmldom/releases/tag/0.9.11","name":"https://github.com/xmldom/xmldom/releases/tag/0.9.11","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-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1333","lang":"en","description":"CWE-1333: Inefficient Regular Expression Complexity","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-01T14:21:27.215Z"},"source":{"advisory":"GHSA-g53g-w8rj-fmg7","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-01T14:57:15.918491Z","id":"CVE-2026-83606","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":"2026-09-01T14:57:43.875Z"}}]}}}