What is the CVSS score of CVE-2026-25543?

CVE-2026-25543 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of .NET are affected by CVE-2026-25543?

Organizations using HtmlSanitizer should be aware of moderate risk from CVE-2026-25543 rated CVSS 6.1. Exploitation could compromise the security of affected deployments.. A patch is available.

.NET CVE-2026-25543

MEDIUM

Improper Encoding or Escaping of Output (CWE-116)

2026-02-04 security-advisories@github.com

GHSA-j92c-7v7g-gj3f

.NET XSS Htmlsanitizer

6.1

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.1 MEDIUM

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 21:54 vuln.today

Patch released

Feb 24, 2026 - 21:29 nvd

Patch available

CVE Published

Feb 04, 2026 - 22:16 nvd

MEDIUM 6.1

DescriptionGitHub Advisory

HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta.

AnalysisAI

Htmlsanitizer versions up to 9.0.892 is affected by improper encoding or escaping of output (CVSS 6.1).

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Vulnerability AssessmentAI

Risk Assessment	CVSS 6.1 (MEDIUM). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	An attacker could exploit this vulnerability to XSS attacks.
Remediation	A vendor patch is available — apply it immediately. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. …

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CVE-2026-25543 vulnerability details – vuln.today

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