CVE-2026-46640

Description

### Description The `obj.(expr)` dynamic-attribute syntax (added in 3.15.0 as the replacement for the deprecated `attribute()` function) lets the attribute be an arbitrary expression. When the receiver is `_self` (or any `{% import %}` alias) and the parenthesised expression is a string literal, `DotExpressionParser` short-circuits to the macro-call path and concatenates the attacker-controlled string into a `MacroReferenceExpression` name with no identifier validation. `MacroReferenceExpression::compile()` then emits that name raw into the generated PHP source. An attacker who can supply template source can inject arbitrary PHP into the compiled template and execute it at template-load time, before `checkSecurity()` is ever called. This is a complete bypass of `SandboxExtension`, including a globally-enabled sandbox with an empty `SecurityPolicy` allowlist. ### Resolution The parser now validates that the dynamic attribute resolves to a valid macro identifier before routing through `MacroReferenceExpression`, and the macro-reference compiler emits the name through a properly escaped path. ### Credits Twig would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

How to fix CVE-2026-46640

To remediate CVE-2026-46640, upgrade the affected package to a fixed version below.

• —no fix listed
• —upgrade to 3.26.0 or later

Is CVE-2026-46640 being exploited?

No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-46640.

Affected packages (2)

• from 0
• >= 3.15.0, < 3.26.0

CVSS scores

References (6)

• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-46640
• PATCHgithub.com/twigphp/Twig
• WEBgithub.com/FriendsOfPHP/security-advisories/blob/master/twig/twig/CVE-2026-46640.yaml
• WEBgithub.com/twigphp/Twig/security/advisories/GHSA-45vw-wh46-2vx8