CVE-2026-9558 json
Mautic has Server-Side Template Injection (SSTI) in Theme Templates
published 2026-05-29 5 mo ago modified 2026-09-10 1 mo ago also GHSA-9fx4-7cmj-47vg , EUVD-2026-33276
- cvss
- 9.9
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 47%
- public exploits
- 0
- none known
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 on the hosting server (Remote Code Execution) or access restricted system files and configuration settings.
Patch / fix
- packagist mautic/core 5.2.11, 6.0.9, 7.1.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 5 mo ago
Exploit prediction
0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | mautic/core | >=1.3.0 >=5.0.0, <5.2.11 >=6.0.0, <6.0.9 >=7.0.0, <7.1.2 |
5.2.11 6.0.9 7.1.2 |
Classification
- Weakness
-
- CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine
References
Sources
- CVE List CVE-2026-9558
- GitHub Advisory GHSA-9fx4-7cmj-47vg
- NVD CVE-2026-9558
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