CVE-2026-9558 (GCVE-0-2026-9558)

Vulnerability from cvelistv5 – Published: 2026-05-29 10:01 – Updated: 2026-05-29 10:49
VLAI
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.
Severity
9.9 (Critical)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-1336 - Improper Neutralization of Special Elements Used in a Template Engine
Assigner
References
Impacted products
Vendor Product Version
Affected: 1.3.0 , < 4.4.20 (semver)
Affected: 5.0.0 , < 5.2.11 (semver)
Affected: 6.0.0 , < 6.0.9 (semver)
Affected: 7.0.0 , < 7.1.2 (semver)
Credits
Onurcan Genç (@onurcangnc) Daniel Zhang (@xfer0) Tuan Do (@Entropt) Patryk Gruszka (@patrykgruszka) John Linhart (@escopecz) Leuchtfeuer Digital Marketing (@Leuchtfeuer)
Show details on NVD website
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.