CVE-2026-54570AngleSharp: HTML5 Spec Compliance: mXSS via annotation-xml HTML Integration Point Bypass
- 6.9MediumCVSS base score
- 0.33%Exploitation in 30 daysEPSS · top 73% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/AngleSharp/AngleSharp/security/advisories/GHSA-pgww-w46g-26qg (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 2 months later
· 2 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.33% · top 73% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.
Affected products
- affected < 1.5.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- NuGetAngleSharpGHSA-pgww-w46g-26qg (opens in a new tab)
References
References3
- https://github.com/AngleSharp/AngleSharp/security/advisories/GHSA-pgww-w46g-26qg (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/AngleSharp/AngleSharp/commit/8033a5c690af9c2c443f58e34875343fa4cc1d07 (opens in a new tab)x_refsource_MISC
- https://github.com/AngleSharp/AngleSharp/releases/tag/1.5.0 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-61128 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-pgww-w46g-26qg (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-54570)Record last updated .