{"id":"CVE-2026-26278","summary":"fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)","details":"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.","aliases":["GHSA-jmr7-xgp7-cmfj"],"modified":"2026-03-20T12:48:24.833378Z","published":"2026-02-19T19:40:55.842Z","related":["CGA-p55m-grjf-6fcf","openSUSE-SU-2026:10236-1"],"database_specific":{"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26278.json","cwe_ids":["CWE-776"]},"references":[{"type":"WEB","url":"https://github.com/NaturalIntelligence/fast-xml-parser/releases/tag/v5.3.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26278.json"},{"type":"ADVISORY","url":"https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-jmr7-xgp7-cmfj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26278"},{"type":"FIX","url":"https://github.com/NaturalIntelligence/fast-xml-parser/commit/910dae5be2de2955e968558fadf6e8f74f117a77"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/naturalintelligence/fast-xml-parser","events":[{"introduced":"2f7d138af8338aaf65c1d98902f76259c7233373"},{"fixed":"ecb2ca118ad3d6c62f2cc90416b58da24db5d18b"}],"database_specific":{"versions":[{"introduced":"5.0.0"},{"fixed":"5.3.6"}]}},{"type":"GIT","repo":"https://github.com/naturalintelligence/fast-xml-parser","events":[{"introduced":"292fb784334043214e29fa60adbb5630a36f5768"},{"fixed":"d4eb6b4713a8d11e6730943392419040898ecbc0"}],"database_specific":{"versions":[{"introduced":"4.1.3"},{"fixed":"4.5.4"}]}}],"versions":["v4.1.3","v4.1.4","v4.2.0","v4.2.3","v4.2.4","v4.2.5","v4.2.6","v4.2.7","v4.3.0","v4.3.1","v4.3.2","v4.3.3","v4.3.4","v4.3.5","v4.3.6","v4.4.0","v4.4.1","v4.5.0","v4.5.1","v4.5.2","v4.5.3","v5.0.0","v5.0.2","v5.0.4","v5.0.6","v5.0.7","v5.0.9","v5.1.0","v5.2.0","v5.2.1","v5.2.2","v5.2.3","v5.2.5","v5.3.0","v5.3.1","v5.3.2","v5.3.3","v5.3.4","v5.3.5"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-26278.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}