{"id":"CVE-2026-54570","title":"AngleSharp is a .NET library for parsing angle bracket based hyper-texts","summary":"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 encodin…","severity":"medium","cvss":6.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N","cwe":["CWE-80"],"vendor":"AngleSharp","product":"AngleSharp","affected":["AngleSharp < 1.5.0"],"patched":["AngleSharp 1.5.0"],"published":"2026-08-18","updated":"2026-09-18","sourceUpdated":"2026-09-18T20:09:01.757","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-54570","references":[{"url":"https://github.com/AngleSharp/AngleSharp/commit/8033a5c690af9c2c443f58e34875343fa4cc1d07","label":"security-advisories@github.com"},{"url":"https://github.com/AngleSharp/AngleSharp/releases/tag/1.5.0","label":"security-advisories@github.com"},{"url":"https://github.com/AngleSharp/AngleSharp/security/advisories/GHSA-pgww-w46g-26qg","label":"security-advisories@github.com"},{"url":"https://github.com/AngleSharp/AngleSharp/security/advisories/GHSA-pgww-w46g-26qg","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/advisories/GHSA-pgww-w46g-26qg"}],"tags":["nvd","ghsa","nuget"],"epss":0.0031,"epssPercentile":0.23969,"aliases":["GHSA-pgww-w46g-26qg"],"ecosystem":"nuget","ingestedAt":"2026-07-17T22:16:59.738Z","slug":"CVE-2026-54570","body":"## Overview\n\nAngleSharp 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-54570)\n\nAffected packages:\n\n- `AngleSharp < 1.5.0`\n\nPatched in:\n\n- `AngleSharp 1.5.0`\n\nSource: https://github.com/advisories/GHSA-pgww-w46g-26qg","depth":"sunlit","depthScore":38,"depthScoreParts":{"impact":38,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}