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, URL, and other contexts where the output is not properly escaped. This issue is fixed in version 3.26.0.
EPSS: 0.003 (22.7th percentile) — read the EPSS interpretation.
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.