~ / search / GHSA-mm6w-gr99-p3jj

GHSA-mm6w-gr99-p3jj

Twig: Sandbox property and method bypass via object-destructuring assignment

Source: GitHub Advisory Database (reviewed) High CVE-2026-46639

Packages

EcosystemPackageAffectedFixed in
Packagist twig/twig >= 3.24.0, < 3.26.0 3.26.0

Details

As written in the advisory (Markdown source, shown as plain text).

### 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.

References

External links from the advisory. They lead to third-party sites.