CVE-2026-45753CWE-184CWE-79

Symfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)

Low · published July 14, 2026

CVSS v4.0
2.1
EPSS
0%
Percentile
26.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
2.1 · LOW
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
EPSS
0.00338 · 26.0th percentile
Weaknesses
CWE-184 · Incomplete List of Disallowed Inputs; CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-07-14T18:21Z
EPSS history
Timeline
  • 14 JUL 18:21Z
    Symfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)
    cvelistv5