CVE-2025-66299 HIGH

CVE-2025-66299: Security Sandbox Bypass with SSTI (Server Side Template Injection) in the Grav CMS

Vendor Getgrav
Product grav
Weakness CWE-94 · Code injection
Published December 1, 2025
Last update December 2, 2025
View on NVD All CVEs

CVSS base score

8.8/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

December 1, 2025 CVE published
December 2, 2025 Record updated

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04Related CVE

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