GHSA-mm6w-gr99-p3jjHigh
Twig: Sandbox property and method bypass via object-destructuring assignment
🔗 CVE IDs covered (1)
📋 Description
### Description
The object-destructuring assignment syntax introduced in Twig 3.24.0 generates a call to `CoreExtension::getAttribute()` with the `$sandboxed` argument hardcoded to `false`, regardless of whether a `SandboxExtension` is active. This permanently disables the sandbox's property and method policy checks for every destructuring expression.
`ObjectDestructuringSetBinary::compile()` emits:
```php
CoreExtension::getAttribute($this->env, $this->source, ..., \Twig\Template::ANY_CALL, false, false, false, ...);
// ^^^^^
// sandbox check never runs
```
Whereas `GetAttrExpression::compile()` correctly passes `$env->hasExtension(SandboxExtension::class)`.
An attacker with write access to a sandboxed Twig template can read any public property or invoke any public getter on objects passed to the template engine, bypassing `SecurityPolicy` restrictions. The exploit requires only the `{% do %}` tag to be in `allowedTags`, which is a common configuration.
### Resolution
The destructuring compiler now forwards the active sandbox flag to `getAttribute()` so property/method allowlists are enforced.
### Credits
Twig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting and fixing the issue.
🎯 Affected products1
- composer/twig/twig:>= 3.24.0, < 3.26.0