---
id: "CVE-2026-115189"
kind: "vulnerability"
aliases: ["CVE-2026-115189"]
title: "Mautic: Twig theme sandbox escape lets an uploaded theme run server code"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mautic", "package", "php", "self-hosted"]
not_affected_if: ["managed-hosting", "theme-upload-disabled"]
published_at: "2026-10-26T14:16:30+00:00"
first_seen_at: "2026-10-26T14:30:36+00:00"
updated_at: "2026-10-26T14:32:07+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-115189", "first_seen_at": "2026-10-26T14:30:36+00:00"}]
---

# Mautic: Twig theme sandbox escape lets an uploaded theme run server code

Mautic's sandbox for user-uploaded Twig theme templates does not fully restrict them, so a crafted theme can escape it. An authenticated user with the core:themes:create permission can run operating system commands on the server, read config files and database credentials, write files, and reach internal services.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Mautic version against the fixed release in the advisory (unknown in the sources)
- Check which roles hold `core:themes:create` in Mautic's permission settings; the Administrator role has it by default

## Fix

- Upgrade Mautic to a release that completes the fix for GHSA-9fx4-7cmj-47vg (fixed version unknown in the sources)
- Remove `core:themes:create` from roles that do not need to upload themes until patched

## Timeline

- 2026-10-26T14:30:36+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-115189

## From the sources

A server-side template injection vulnerability exists in the Twig theme rendering sandbox of Mautic. The sandbox introduced to restrict user-uploaded theme templates (the fix for GHSA-9fx4-7cmj-47vg) does not fully enforce its restrictions, allowing a crafted theme template to escape the sandbox. An authenticated user with the core:themes:create permission can upload a malicious theme whose template is later rendered, resulting in execution of arbitrary code on the server with the privileges of the web server process. This allows the attacker to execute operating system commands, read server-side files including configuration files and database credentials, write files, and reach internal services. In default installations the core:themes:create permission is granted to the Administrator role, and in multi-operator setups it may be delegated to other roles. This is an incomplete fix for GHSA-9fx4-7cmj-47vg.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_