PT-2026-42635 · Packagist · Twig/Twig

Publicado

2026-05-21

·

Atualizado

2026-05-21

CVSS v4.0

8.7

Alta

VetorAV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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, ..., TwigTemplate::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.

Exploit

Correção

Protection Mechanism Failure

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Enumeração de Fraquezas

Identificadores relacionados

GHSA-MM6W-GR99-P3JJ

Produtos afetados

Twig/Twig