9.9
CRITICAL CVSS 3.1
CVE-2026-9558
Mautic Twig Template Injection Vulnerability
Description

A Server-Side Template Injection (SSTI) vulnerability exists in Mautic's theme engine. The platform renders uploaded Twig templates without a sandbox or strict function restrictions. Authenticated users with permissions to create or upload themes can abuse this to execute arbitrary code on the hosting server (Remote Code Execution) or access restricted system files and configuration settings.

INFO

Published Date :

May 29, 2026, 11:16 a.m.

Last Modified :

July 21, 2026, 12:10 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-9558 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Acquia mautic
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 CRITICAL 4e531c38-7a33-45d3-98dd-d909c0d8852e
CVSS 3.1 CRITICAL [email protected]
Solution
Update Mautic to the latest version to patch SSTI and prevent RCE. Limit theme upload permissions.
  • Update Mautic to the latest version.
  • Restrict theme upload permissions.
  • Review uploaded themes for malicious code.
Public PoC/Exploit Available at Github

CVE-2026-9558 has a 2 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-9558.

URL Resource
https://github.com/mautic/mautic/security/advisories/GHSA-9fx4-7cmj-47vg
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-9558 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-9558 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Exploitability PoC for CVE-2026-9558 (SSTI Mautic Theme)

Shell Twig

Updated: 1 week, 4 days ago
0 stars 0 fork 0 watcher
Born at : July 10, 2026, 12:13 p.m. This repo has been linked 1 different CVEs too.

📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.

security cve exploit poc vulnerability

Updated: 4 days, 13 hours ago
7922 stars 1275 fork 1275 watcher
Born at : Dec. 8, 2019, 1:03 p.m. This repo has been linked 646 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-9558 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-9558 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Translated by [email protected]

    Jul. 21, 2026

    Action Type Old Value New Value
    Added Translation Title: varias versiones de Mautic, Description: Una vulnerabilidad de inyección de plantillas del lado del servidor (SSTI) existe en el motor de temas de Mautic. La plataforma renderiza plantillas Twig subidas sin un sandbox o restricciones estrictas de funciones. Usuarios autenticados con permisos para crear o subir temas pueden abusar de esto para ejecutar código arbitrario en el servidor de alojamiento (Ejecución remota de código) o acceder a archivos de sistema restringidos y configuraciones.
  • CVE Modified by [email protected]

    Jun. 17, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://github.com/mautic/mautic', 'versions': [{'status': 'affected', 'version': '1.3.0', 'lessThan': '4.4.20', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.0.0', 'lessThan': '5.2.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.0.0', 'lessThan': '6.0.9', 'versionType': 'semver'}, {'status': 'affected', 'version': '7.0.0', 'lessThan': '7.1.2', 'versionType': 'semver'}], 'packageName': 'mautic/core', 'collectionURL': 'https://packagist.org', 'defaultStatus': 'unaffected'}]
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Jun. 17, 2026

    Action Type Old Value New Value
    Added SSVC {'id': 'CVE-2026-9558', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-05-29T10:48:50.985840Z'}
  • New CVE Received by [email protected]

    May. 29, 2026

    Action Type Old Value New Value
    Added Description A Server-Side Template Injection (SSTI) vulnerability exists in Mautic's theme engine. The platform renders uploaded Twig templates without a sandbox or strict function restrictions. Authenticated users with permissions to create or upload themes can abuse this to execute arbitrary code on the hosting server (Remote Code Execution) or access restricted system files and configuration settings.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    Added CWE CWE-1336
    Added Reference https://github.com/mautic/mautic/security/advisories/GHSA-9fx4-7cmj-47vg
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.