{"cve":"CVE-2026-26278","nvd":{"published":"2026-02-19T20:25:43.717","modified":"2026-09-10T13:17:56.203","status":"Modified","description":"fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.","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/910dae5be2de2955e968558fadf6e8f74f117a77","https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.6","https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jmr7-xgp7-cmfj","https://access.redhat.com/errata/RHSA-2026:40984","https://access.redhat.com/errata/RHSA-2026:41941"],"products":["naturalintelligence:fast-xml-parser"],"source":"nvd","synced_at":"2026-10-19T22:23:35.260773158+00:00"},"epss":{"cve":"CVE-2026-26278","score":0.00937,"percentile":0.60866,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-jmr7-xgp7-cmfj","url":"https://osv.dev/vulnerability/GHSA-jmr7-xgp7-cmfj","summary":"fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)","modified":"2026-09-10T03:50:35.274601096Z","packages":[{"ecosystem":"npm","name":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","ranges":[">=4.1.3 <4.5.4"],"fixed":["4.5.4"]},{"ecosystem":"npm","name":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","ranges":[">=5.0.0 <5.3.6"],"fixed":["5.3.6"]}]}],"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."]}