SEPTEMBER 18, 2026
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Case File

CVE-2026-54570

MEDIUM · CVSS 6.9 EPSS 0.25% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-18 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

The AngleSharp library, prior to version 1.5.0, is vulnerable due to improper handling of the MathAnnotationXmlElement, which can lead to mutation cross-site scripting (XSS) attacks. This occurs when an attacker exploits the differential in namespace handling to inject active script-capable HTML that is not sanitized correctly. Developers and organizations using AngleSharp for parsing HTML or XML should prioritize upgrading to version 1.5.0 to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-54570
Severity
MEDIUM
CVSS
6.9
EPSS
0.25%

Original NVD 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.