CVE-2026-54570 — MEDIUM (6.9)

Vulnerability Description

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.

CVSS Score

6.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

LOW

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-80

References

FAQ

What is CVE-2026-54570?

CVE-2026-54570 is a vulnerability with a CVSS score of 6.9 (MEDIUM). 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 HT...

How severe is CVE-2026-54570?

CVE-2026-54570 has been rated MEDIUM with a CVSS base score of 6.9/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-54570?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.