Grav is a file-based Web platform. Prior to 1.8.0-beta.27, Grav CMS is vulnerable to a Server-Side Template Injection (SSTI) that allows any authenticated user with editor permissions to execute arbitrary code on the remote server, bypassing the existing security sandbox. Since the security sandbox does not fully protect the Twig object, it is possible to interact with it (e.g., call methods, read/write attributes) through maliciously crafted Twig template directives injected into a web page. This allows an authenticated editor to add arbitrary functions to the Twig attribute system.twig.safe_filters, effectively bypassing the Grav CMS sandbox. This vulnerability is fixed in 1.8.0-beta.27.
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Fixes

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Workaround

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History

Mon, 01 Dec 2025 21:30:00 +0000

Type Values Removed Values Added
Description Grav is a file-based Web platform. Prior to 1.8.0-beta.27, Grav CMS is vulnerable to a Server-Side Template Injection (SSTI) that allows any authenticated user with editor permissions to execute arbitrary code on the remote server, bypassing the existing security sandbox. Since the security sandbox does not fully protect the Twig object, it is possible to interact with it (e.g., call methods, read/write attributes) through maliciously crafted Twig template directives injected into a web page. This allows an authenticated editor to add arbitrary functions to the Twig attribute system.twig.safe_filters, effectively bypassing the Grav CMS sandbox. This vulnerability is fixed in 1.8.0-beta.27.
Title Security Sandbox Bypass with SSTI (Server Side Template Injection) in the Grav CMS
Weaknesses CWE-1336
CWE-94
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-12-01T21:15:11.704Z

Reserved: 2025-11-26T23:11:46.393Z

Link: CVE-2025-66299

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-12-01T22:15:49.290

Modified: 2025-12-01T22:15:49.290

Link: CVE-2025-66299

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.