CVE-2025-66021

Description

OWASP Java HTML Sanitizer is a configureable HTML Sanitizer written in Java, allowing inclusion of HTML authored by third-parties in web applications while protecting against XSS. In version 20240325.1, OWASP java html sanitizer is vulnerable to XSS if HtmlPolicyBuilder allows noscript and style tags with allowTextIn inside the style tag. This could lead to XSS if the payload is crafted in such a way that it does not sanitise the CSS and allows tags which is not mentioned in HTML policy. At time of publication no known patch is available.

CVSS v3.1 Score

6.1

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
owasp	java_html_sanitizer	All

References

Advisories & Patches

https://github.com/OWASP/java-html-sanitizer/security/advisories/GHSA-g9gq-3pfx-2gw2 https://github.com/OWASP/java-html-sanitizer/security/advisories/GHSA-g9gq-3pfx-2gw2

Exploits

https://github.com/OWASP/java-html-sanitizer/security/advisories/GHSA-g9gq-3pfx-2gw2 https://github.com/OWASP/java-html-sanitizer/security/advisories/GHSA-g9gq-3pfx-2gw2

Frequently Asked Questions

What is CVE-2025-66021? +

OWASP Java HTML Sanitizer is a configureable HTML Sanitizer written in Java, allowing inclusion of HTML authored by third-parties in web applications while protecting against XSS. In version 20240325.1, OWASP java html sanitizer is vulnerable to XSS if HtmlPolicyBuilder allows noscript and style tags with allowTextIn inside the style tag. This could lead to XSS if the payload is crafted in such a way that it does not sanitise the CSS and allows tags which is not mentioned in HTML policy. At time of publication no known patch is available. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2025-66021? +

CVE-2025-66021 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-66021? +

CVE-2025-66021 affects products from owasp, specifically: java_html_sanitizer. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-66021? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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