Not a U.S. government website. NDD is an independent vulnerability database by Volerion and is not affiliated with or endorsed by NIST or NVD.

CVE-2026-9558 Details

ANALYZED

This CVE record has been analyzed and enriched by NVDAPI.com as an independent party.

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:9.9 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CNA: [email protected]CVSS-B:9.9 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.

URL	Source(s)	Tag(s)
https://github.com/mautic/mautic/security/advisories/GHSA-9fx4-7cmj-47vg	[email protected]	AdvisoryRemedyVendor

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-1336	Improper Neutralization of Special Elements Used in a Template Engine	[email protected]

Affected Products

Product	Versions
Mautic	<= 1.3.0 (semver)
CPE cpe:2.3:a:mautic:mautic:::::::: Remediation Upgrade: 7.1.2moderate effort Upgrade: 6.0.9moderate effort Upgrade: 5.2.11moderate effort Upgrade: 4.4.20moderate effort Mitigation:low effort Restrict theme upload and creation permissions (core:themes:create) to only highly trusted administrators.

Change History

4 change records found show changes

Date	Action	Recorded By
Jul 21, 2026	CVE Translated	[email protected]
Jun 17, 2026	CVE Modified	[email protected]
Jun 17, 2026	CVE Modified	CISA-ADP
May 29, 2026	New CVE Received	[email protected]