{"id":"CVE-2026-83606","summary":"xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions","details":"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 ?\u003e 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.","aliases":["GHSA-g53g-w8rj-fmg7"],"modified":"2026-09-03T03:48:17.126365711Z","published":"2026-09-01T14:21:27.215Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-1333","CWE-400"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/83xxx/CVE-2026-83606.json"},"references":[{"type":"WEB","url":"https://github.com/xmldom/xmldom/releases/tag/0.9.11"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/83xxx/CVE-2026-83606.json"},{"type":"ADVISORY","url":"https://github.com/xmldom/xmldom/security/advisories/GHSA-g53g-w8rj-fmg7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-83606"},{"type":"FIX","url":"https://github.com/xmldom/xmldom/commit/73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e"},{"type":"FIX","url":"https://github.com/xmldom/xmldom/pull/1039"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/xmldom/xmldom","events":[{"introduced":"48953f6e6d1d49093c8014c4585b31833de78812"},{"fixed":"73df6b8bdbd86f904b9e8c3ab9c49aa54ef2802e"},{"fixed":"1f0610959ab7b82cc7ad702d1be0243efc5791c0"}],"database_specific":{"extracted_events":[{"introduced":"0.9.0-beta.9"},{"fixed":"0.9.11"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["0.9.10","0.9.9","0.9.8","0.9.7","0.9.6","0.9.5","0.9.4","0.9.3","0.9.2","0.9.1","0.9.0","0.9.0-beta.11","0.9.0-beta.10","0.9.0-beta.9"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-83606.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"}]}