CVE-2026-9558

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

29/05/2026

Last modified:

29/05/2026

Description

A Server-Side Template Injection (SSTI) vulnerability exists in Mautic&#39;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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 9.90 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

9.90

Severity 3.x

CRITICAL

References to Advisories, Solutions, and Tools

https://github.com/mautic/mautic/security/advisories/GHSA-9fx4-7cmj-47vg