CVE-2026-45753

NameCVE-2026-45753
DescriptionSymfony 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6312-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
symfony (PTS)bullseye4.4.19+dfsg-2+deb11u6fixed
bullseye (security)4.4.19+dfsg-2+deb11u7fixed
bookworm, bookworm (security)5.4.53+dfsg-0+deb12u1fixed
trixie, trixie (security)6.4.41+dfsg-0+deb13u1fixed
forky, sid7.4.14+dfsg-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
symfonysourcebullseye(not affected)
symfonysourcebookworm(not affected)
symfonysourcetrixie6.4.41+dfsg-0+deb13u1DSA-6312-1
symfonysource(unstable)7.4.12+dfsg-1

Notes

[bookworm] - symfony <not-affected> (Vulnerable code not present, introduced in 6.1)
[bullseye] - symfony <not-affected> (Vulnerable code not present, introduced in 6.1)
https://symfony.com/blog/cve-2026-45753-htmlsanitizer-urlattributesanitizer-omits-action-formaction-poster-cite-javascript-uri-survives-sanitization-xss

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