{"id":"GHSA-mm6w-gr99-p3jj","summary":"Twig: Sandbox property and method bypass via object-destructuring assignment","details":"### Description\n\nThe object-destructuring assignment syntax introduced in Twig 3.24.0 generates a call to `CoreExtension::getAttribute()` with the `$sandboxed` argument hardcoded to `false`, regardless of whether a `SandboxExtension` is active. This permanently disables the sandbox's property and method policy checks for every destructuring expression.\n\n`ObjectDestructuringSetBinary::compile()` emits:\n\n```php\nCoreExtension::getAttribute($this-\u003eenv, $this-\u003esource, ..., \\Twig\\Template::ANY_CALL, false, false, false, ...);\n//                                                                                ^^^^^\n//                                                                       sandbox check never runs\n```\n\nWhereas `GetAttrExpression::compile()` correctly passes `$env-\u003ehasExtension(SandboxExtension::class)`.\n\nAn 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.\n\n### Resolution\n\nThe destructuring compiler now forwards the active sandbox flag to `getAttribute()` so property/method allowlists are enforced.\n\n### Credits\n\nTwig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting and fixing the issue.","aliases":["CVE-2026-46639"],"modified":"2026-09-10T03:51:06.512482823Z","published":"2026-05-21T21:30:49Z","database_specific":{"cwe_ids":["CWE-693"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-05-21T21:30:49Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/twigphp/Twig/security/advisories/GHSA-mm6w-gr99-p3jj"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/twig/twig/CVE-2026-46639.yaml"},{"type":"PACKAGE","url":"https://github.com/twigphp/Twig"},{"type":"WEB","url":"https://symfony.com/cve-2026-46639"}],"affected":[{"package":{"name":"twig/twig","ecosystem":"Packagist","purl":"pkg:composer/twig/twig"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.24.0"},{"fixed":"3.26.0"}]}],"versions":["v3.24.0","v3.25.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-mm6w-gr99-p3jj/GHSA-mm6w-gr99-p3jj.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}