critical CVSS 9.8

CVE-2026-46633·PHP vulnerability

Twig is a template language for PHP. Prior to 3.26.0, Compiler::string() does not escape single quotes when a template name from a {% use %} tag is placed inside a PHP single-quoted string literal, allowing a crafted template name to terminate the string and inject arbitrary PHP expressions into the compiled cache file. This issue is fixed in version 3.26.0.

Severity
critical
Software
PHP
Fixed in
3.26.0
Published
2026-07-14

Affected versions

Until: 3.26.0

Fixed in: 3.26.0

How to fix this CVE

Update PHP and the Twig template engine to version 3.26.0 or later to patch a critical template injection vulnerability. The flaw allows attackers to inject arbitrary PHP code through maliciously crafted template names in {% use %} tags, which could lead to remote code execution when the compiled cache file is processed. Immediately apply this update to all production and development systems running affected versions.

sudo dnf update php

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'php -v' to check your current PHP version and note the version number
  2. Run 'php -m | grep twig' or check composer.json/composer.lock for Twig version; if Twig version is below 3.26.0, the system is vulnerable
  3. Search application logs and web server access logs for template file paths containing unusual characters or quotes (e.g., single quotes in {% use %} tag arguments)
  4. After patching, re-run 'php -v' and verify Twig is at 3.26.0+; delete the Twig compilation cache directory (typically var/cache/) and restart the application to ensure new bytecode is generated

FAQ

What is CVE-2026-46633?

CVE-2026-46633 is a critical vulnerability in Twig's template compiler that fails to properly escape single quotes in template names within {% use %} statements, enabling attackers to break out of PHP string literals and execute arbitrary code in the compiled cache file.

Is CVE-2026-46633 being actively exploited?

No, CVE-2026-46633 is not listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available, but the critical CVSS 9.8 score and ease of exploitation mean immediate patching is essential.

What versions of PHP are affected by CVE-2026-46633?

All versions of PHP using Twig prior to version 3.26.0 are affected. The vulnerability exists in the Twig template engine itself, which is commonly used with PHP applications.

How do I check if my server is vulnerable to CVE-2026-46633?

Run 'composer show symfony/twig-bundle' or check your vendor/twig directory; if the installed Twig version is below 3.26.0, your server is vulnerable. Alternatively, inspect compiled template files in your cache directory for signs of injected PHP code.

Does Defensia detect CVE-2026-46633?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If PHP or Twig is installed on a monitored server, CVE-2026-46633 will appear in your dashboard with remediation steps.

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References

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