{"cve":"CVE-2026-33036","nvd":{"published":"2026-03-20T06:16:11.630","modified":"2026-06-17T10:36:50.727","status":"Analyzed","description":"fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like &#65; can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-776"],"references":["https://github.com/NaturalIntelligence/fast-xml-parser/commit/bd26122c838e6a55e7d7ac49b4ccc01a49999a01","https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.5.6","https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-8gc5-j5rx-235r"],"products":["naturalintelligence:fast-xml-parser"],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-33036","score":0.00599,"percentile":0.48674,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-8gc5-j5rx-235r","url":"https://osv.dev/vulnerability/GHSA-8gc5-j5rx-235r","summary":"fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)","modified":"2026-09-10T03:50:38.199635360Z","packages":[{"ecosystem":"npm","name":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","ranges":[">=5.0.0 <5.5.6"],"fixed":["5.5.6"]},{"ecosystem":"npm","name":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","ranges":[">=4.0.0-beta.3 <4.5.5"],"fixed":["4.5.5"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}