{"items":[{"id":"NVI-00014144","kind":"vulnerability","title":"xmldom PI grammar regex ReDoS: quadratic backtracking on unterminated processing instructions","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-g53g-w8rj-fmg7","CVE-2026-83606"],"plain_summary":"GitHub lists this reviewed advisory for @xmldom/xmldom. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-4fe21b45a302249e821c66d51583140a"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-4fe21b45a302249e821c66d51583140a","url":"https://github.com/advisories/GHSA-g53g-w8rj-fmg7","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-g53g-w8rj-fmg7","publisher":"GitHub Advisory Database","observed_at":"2026-11-02T02:20:31.767Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-4fe21b45a302249e821c66d51583140a"],"technology":"@xmldom/xmldom","known_exclusions":[],"conditions_summary":"## Summary\n\n`@xmldom/xmldom`'s processing-instruction (PI) grammar regex exhibits quadratic-time backtracking\n(ReDoS) when parsing an **unterminated** processing instruction. A single small XML document\ncontaining `` forces the regular\nexpression engine into O(n²) work, stalling the Node.js event loop. The input is parsed with\n`DOMParser.parseFromString` under **default options**, so it is reachable from unauthenticated,\nnetwork-delivered XML (SOAP/SAML, webhooks, uploads, XML APIs).\n\n## Details\n\nThe PI production in `lib/grammar.js` compiles (flags `mu`) to:\n\n```\n^\n                     ^^^ S+ greedy       ^^^ Char*? lazy\n```\n\n- `lib/grammar.js` line 261: https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/grammar.js#L261\n\nIn the optional tail `(?:S+(Char*?))?`, both the greedy separator `S+` and the lazy data `Char*?`\nmatch XML whitespace. When the required trailing `?>` is absent, the engine must ultimately fail —\nbut first it tries every partition of the whitespace run between `S+` and `Char*?`, which is O(n²)\nin the length of the trailing","public_affected_ranges":[">= 0.9.0-beta.9, <= 0.9.10"]}],"null_published_at":"2026-11-02T10:00:37.213Z","source_updated_at":"2026-09-08T20:31:51.000Z","source_disclosed_at":"2026-09-08T20:31:50.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-02T02:20:31.767Z"}],"next_cursor":null,"snapshot_revision":"42594"}