How to fix CVE-2025-52561?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Is HTMLSanitizer.jl affected by CVE-2025-52561?

Organizations using HTMLSanitizer.jl should be aware of notable risk from CVE-2025-52561, a cross-site scripting vulnerability rated CVSS 6.9. Attackers could inject scripts to steal sessions or perform actions as authenticated users.

HTMLSanitizer.jl CVE-2025-52561

EUVD-2025-28447 MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2025-06-23 [email protected]

XSS

6.9

CVSS 4.0

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Lifecycle Timeline

Patch available

Apr 16, 2026 - 05:29 EUVD

0.2.1

Analysis Generated

Mar 15, 2026 - 22:10 vuln.today

EUVD ID Assigned

Mar 15, 2026 - 22:10 euvd

EUVD-2025-28447

CVE Published

Jun 23, 2025 - 21:15 nvd

MEDIUM 6.9

DescriptionNVD

HTMLSanitizer.jl is a Whitelist-based HTML sanitizer. Prior to version 0.2.1, when adding the style tag to the whitelist, content inside the tag is incorrectly unescaped, and closing tags injected as content are interpreted as real HTML, enabling tag injection and JavaScript execution. This could result in possible cross-site scripting (XSS) in any HTML that is sanitized with this library. This issue has been patched in version 0.2.1. A workaround involves adding the math and svg elements to the whitelist manually.

Analysis

Technical ContextAI

Cross-site scripting (XSS) allows injection of client-side scripts into web pages viewed by other users due to insufficient output encoding.

RemediationAI

Encode all user-supplied output contextually (HTML, JS, URL). Implement Content Security Policy (CSP) headers. Use HTTPOnly and Secure cookie flags.

CVE-2025-52561 vulnerability details – vuln.today

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