twig/twig security advisory

CVE-2026-46640: Arbitrary PHP code execution via _self.(<string>) macro-reference compilation in twig/twig

CVE-2026-46640 is a high-severity remote code execution vulnerability in the PHP package twig/twig (CVSS 8.8), published 14 July 2026. It is fixed in 3.26.0; earlier versions are affected. Exploiting it needs a low-privilege user account.

high 8.8 published 2026-07-14 · updated 2026-10-24

Affected versions: >= 3.15.0, < 3.26.0
Fixed in: 3.26.0
Newest release: 3.30.0
Severity: High · CVSS 8.8
Type: Remote code execution
CWE-94
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Is your twig/twig version affected?

Run composer show twig/twig in your project, then enter the version. We check it against this and every other known twig/twig advisory.

Who can exploit CVE-2026-46640

Access: A normal, low-privilege user account in the app.

CVSS vector (scored by NVD): CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Your app is only exposed if it uses the affected part of twig/twig. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-46640 in twig/twig

Find the installed version: composer show twig/twig. If you never required it yourself, composer why twig/twig shows which package pulls it in.
Update it: composer update twig/twig --with-all-dependencies. You need 3.26.0 or newer.
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "twig/twig": "^3.26.0" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-46640.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for remote code execution issues while the upgrade waits. None of it replaces the fix.

Never pass user-controlled data to unserialize() or to template rendering, and restrict who can edit templates or settings.
Put a web application firewall in front of the app and watch for new PHP files or admin users.
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-46640 advisory

Twig is a template language for PHP. From 3.15.0 until 3.26.0, _self.(<string>) and import-alias dynamic attribute syntax can concatenate an attacker-controlled string into a MacroReferenceExpression name without identifier validation, causing raw PHP to be emitted into the generated template source and executed at template-load time. This issue is fixed in version 3.26.0.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-46640. Advisory title: “Arbitrary PHP code execution via _self.(<string>) macro-reference compilation”.

References

GitHub security advisory GHSA-45vw-wh46-2vx8 github.com
Symfony security advisory symfony.com
Fix commit 324fa60 github.com
Release v3.26.0 github.com

Other twig/twig advisories

Need help patching or upgrading? Laskyr does PHP and Laravel security fixes and upgrades. Tell us what you run and we reply with a plan and a price.

Ask about a fix

Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.