CVE-2026-45753: XSS

Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

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Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

CWE-184 CWE-184

References

Other References

https://github.com/symfony/symfony/commit/487728e7e180a674a6d4c01bd0cb56161cc441b7 https://github.com/symfony/symfony/releases/tag/v6.4.40 https://github.com/symfony/symfony/releases/tag/v7.4.12 https://github.com/symfony/symfony/releases/tag/v8.0.12 https://github.com/symfony/symfony/security/advisories/GHSA-hhg7-c65m-h7ff

Frequently Asked Questions

What is CVE-2026-45753? +

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

How do I check if I'm vulnerable to CVE-2026-45753? +

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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