CVE-2025-49136: listmonk — Exploit & Fix

Description

listmonk is a standalone, self-hosted, newsletter and mailing list manager. Starting in version 4.0.0 and prior to version 5.0.2, the `env` and `expandenv` template functions which is enabled by default in Sprig enables capturing of env variables on host. While this may not be a problem on single-user (super admin) installations, on multi-user installations, this allows non-super-admin users with campaign or template permissions to use the `{{ env }}` template expression to capture sensitive environment variables. Users should upgrade to v5.0.2 to mitigate the issue.

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CVSS v3.1 Score

9.0

CRITICAL

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

Weakness Type (CWE)

CWE-1336 CWE-1336

Affected Products

Vendor	Product	Versions
nadh	listmonk	4.0.0 — 5.0.2

References

Advisories & Patches

https://github.com/knadh/listmonk/commit/d27d2c32cf3af2d0b24e29ea5a686ba149b49b3e https://github.com/knadh/listmonk/security/advisories/GHSA-jc7g-x28f-3v3h https://github.com/knadh/listmonk/security/advisories/GHSA-jc7g-x28f-3v3h

Exploits

https://github.com/knadh/listmonk/security/advisories/GHSA-jc7g-x28f-3v3h https://github.com/knadh/listmonk/security/advisories/GHSA-jc7g-x28f-3v3h

Other References

https://github.com/knadh/listmonk/releases/tag/v5.0.2

Frequently Asked Questions

What is CVE-2025-49136? +

listmonk is a standalone, self-hosted, newsletter and mailing list manager. Starting in version 4.0.0 and prior to version 5.0.2, the `env` and `expandenv` template functions which is enabled by default in Sprig enables capturing of env variables on host. While this may not be a problem on single-user (super admin) installations, on multi-user installations, this allows non-super-admin users with campaign or template permissions to use the `{{ env }}` template expression to capture sensitive environment variables. Users should upgrade to v5.0.2 to mitigate the issue. It has a CVSS v3.1 base score of 9.0 (CRITICAL).

How severe is CVE-2025-49136? +

CVE-2025-49136 has a CVSS v3.1 score of 9.0 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-49136? +

CVE-2025-49136 affects products from nadh, specifically: listmonk. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-49136? +

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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