{"id":"CVE-2026-54570","summary":"AngleSharp: HTML5 Spec Compliance: mXSS via annotation-xml HTML Integration Point Bypass","details":"AngleSharp is a .NET library for parsing angle bracket based hyper-texts. Prior to 1.5.0, MathAnnotationXmlElement in AngleSharp/Mathml/Dom/Internal/MathAnnotationXmlElement.cs is not treated as an HTML integration point when its encoding attribute is text/html or application/xhtml+xml, causing Consume in AngleSharp/Html/Parser/HtmlDomBuilder.cs to route tokens through foreign-content parsing instead of HTML parsing. A sanitizer can therefore observe a different DOM from the browser that reparses the serialized output. An attacker can combine this namespace differential with markup-breaking characters in an attribute value so that an element hidden from the sanitizer becomes active script-capable HTML after browser reparse, resulting in mutation cross-site scripting. This issue is fixed in version 1.5.0.","aliases":["GHSA-pgww-w46g-26qg"],"modified":"2026-09-20T11:30:55.356749312Z","published":"2026-08-18T17:39:51.827Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-80"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54570.json"},"references":[{"type":"WEB","url":"https://github.com/AngleSharp/AngleSharp/releases/tag/1.5.0"},{"type":"ADVISORY","url":"https://github.com/AngleSharp/AngleSharp/security/advisories/GHSA-pgww-w46g-26qg"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54570.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54570"},{"type":"FIX","url":"https://github.com/AngleSharp/AngleSharp/commit/8033a5c690af9c2c443f58e34875343fa4cc1d07"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/anglesharp/anglesharp","events":[{"introduced":"0"},{"fixed":"8033a5c690af9c2c443f58e34875343fa4cc1d07"},{"fixed":"868a3d2f10e191c72e7adc32972e185cce652356"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.5.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["1.4.1-beta.525","1.4.1-beta.508","v1.4.0","1.4.0-beta.496","1.4.0-beta.493","1.3.1","1.2.0","1.1.2","1.1.0","1.0.7","v1.0.6","v1.0.5","v1.0.4","1.0.4-alpha-289","1.0.3","v1.0.2","v1.0.1","1.0.0-alpha-229","v0.17.1","v0.17.0","v0.16.0","v0.12.0","v0.11.0","v0.10.1","v0.10.0","v0.9.9","v0.9.8.1","v0.9.8","v0.9.7","v0.9","v0.8","v0.7","v0.6","v0.5","v0.4","v0.3","v0.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54570.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N"}]}