CVE-2026-48806: Twig: Sandbox `__toString()` policy bypass via dynamic mapping keys

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-14 · updated 2026-10-24
Weakness: CWE-693

Description

Twig is a template language for PHP. Prior to 3.27.0, ArrayExpression does not guard dynamic mapping keys that are coerced to strings, allowing PHP to invoke __toString() on a Stringable object used as a mapping key without calling SandboxExtension::ensureToStringAllowed(). This issue is fixed in version 3.27.0.

Affected products

twigphp Twig: before 3.27.0 — fixed in 3.27.0

How to fix

Upgrade to a fixed version: twigphp Twig 3.27.0. Check the vendor advisory for mitigations.

References

https://github.com/twigphp/Twig/commit/9ff41014639ef0e8eb50ac7669191c309d863105
https://github.com/twigphp/Twig/releases/tag/v3.27.0
https://github.com/twigphp/Twig/security/advisories/GHSA-5v5v-ww74-355v

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