CVE-2026-71291: Bolt CMS Server-Side Template Injection via Unsandboxed allow_twig Field Rendering

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-10-23
Weakness: CWE-1336

Description

Bolt CMS renders content field values through Twig's full application-level Environment with no SandboxExtension registered anywhere in the codebase. In src/Entity/Field.php, getTwigValue calls shouldBeRenderedAsTwig, which gates rendering only on the field definition's allow_twig flag and a regex checking for , , or ; when true, the raw field value is compiled and rendered via with no sandboxing.

Affected products

bolt core: through 6.1

References

https://github.com/bolt/core
https://github.com/bolt/core/blob/6.1/src/Entity/Field.php

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