XSS in Symfony Twig
CVE-2026-46637
Twig is a template language for PHP. Prior to 3.26.0, several filters in twig/markdown-extra and twig/cssinliner-extra are registered with is_safe => [all], causing Twig to treat plain text or HTML output as safe in HTML, JavaScript, CSS…
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Symfony Twig
- Twig Cssinliner-extra — versions < 3.26.0
- Twig Markdown-extra — versions < 3.26.0
- Twigphp Twig — versions < 3.26.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-46637?
- CVE-2026-46637 is a medium-severity vulnerability in Symfony Twig, classified under Improper Encoding or Escaping of Output. CVSS score: 5.4/10. Published 2026-07-14.
- How severe is CVE-2026-46637?
- Medium severity. CVSS v3 base score is 5.4 out of 10.