CVE-2026-9558

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.

CVSS v3.1

9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1

9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS

0.57% chance of exploitation in the next 30 days, 45th percentile

Published

2026-05-29

Proof-of-concept exploits (1)

• covepseng/cve-2026-9558-poc0★ · 2026-07-12

References

• CVE Record
• NVD entry

Related

• CVE-2026-43512
• CVE-2026-43515
• CVE-2026-49352
• CVE-2026-9552
• CVE-2026-9560
• CVE-2026-9551