CVE-2026-9558

criticalCVSS 9.9covered by 1 sourcefirst seen 2026-07-02

Summary 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. Impact An authenticated user with theme upload and creation privileges can bypass boundaries to execute arbitrary system commands on the hosting server (Remote Code Execution) or access restricted system files and configuration settings. Patched Versions This security issue has been addressed in the following releases: - 7.1.2 - 6.0.9 - 5.2.11 For users on Mautic 4.x, this fix is available in: - 4.4.20 via ELTS Mautic strongly recommend upgrading to a patched version immediately. Workarounds There are no official workarounds. To mitigate this vulnerability without upgrading, restrict theme upload and creation permissions (core:themes:create) to only highly trusted administrators.

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Exploitation outlook

Low exploitation risk0.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 35% of all EPSS-scored CVEs.

Advisory coverage (1)

criticalGHSA-9fx4-7cmj-47vg: Mautic has Server-Side Template Injection (SSTI) in Theme Templatesghsa · 2026-07-02

External references

NVD record for CVE-2026-9558

CVE.org record

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