CVE-2021-40219Public exploitNetwork attack vector

Authenticated code execution via unsafe theme rendering

Published Apr 11, 2022 · Updated Jul 9, 2026

Code injection in Bolt CMS 4.2 and earlier allows remote authenticated users to execute arbitrary server-side code through a crafted theme. TemplateController passes an attacker-edited theme template to Twig rendering, where a crafted filter expression invokes the system function. A valid account with theme-editing access is required; assigning the malicious template to a page and requesting that page executes commands with the web process's privileges.

CVSS severity8.8
High
EPSS probability3.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Bolt CMS 4.2 and earlier allows remote authenticated users to execute arbitrary server-side code through a crafted theme. TemplateController passes an attacker-edited theme template to Twig rendering, where a crafted filter expression invokes the system function. A valid account with theme-editing access is required; assigning the malicious template to a page and requesting that page executes commands with the web process's privileges.

The record

CVE
CVE-2021-40219
Published
Apr 11, 2022
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1059.004Unix Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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