CVE-2026-71291 (CVSS 8.8)

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 `self::getTwig()->createTemplate($value)->render(['record' => $this->getContent()])` with no sandboxing. Bolt's own bundled config/bolt/contenttypes.yaml sets `allow_twig: true` on the default "pages" contenttype's content field out of the box. Any user with edit access to that content type (a standard editor role, not just an administrator) can inject a Twig payload such as `{{ ['id']|map('passthru')|join }}` that executes arbitrary OS commands when the content is saved and rendered, achieving remote code execution as the web server user.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0031

Probability of exploitation

0.23%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-1336 CWE-1336

References

Other References

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

Frequently Asked Questions

What is CVE-2026-71291? +

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 `self::getTwig()->createTemplate($value)->render(['record' => $this->getContent()])` with no sandboxing. Bolt's own bundled config/bolt/contenttypes.yaml sets `allow_twig: true` on the default "pages" contenttype's content field out of the box. Any user with edit access to that content type (a standard editor role, not just an administrator) can inject a Twig payload such as `{{ ['id']|map('passthru')|join }}` that executes arbitrary OS commands when the content is saved and rendered, achieving remote code execution as the web server user. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-71291? +

CVE-2026-71291 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0031, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-71291? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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