Security Sandbox Bypass with SSTI (Server Side Template Injection) in the Grav CMS
Summary
| CVE | CVE-2025-66299 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2025-12-01 22:15:49 UTC |
| Updated | 2026-09-26 00:10:00 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 8.8 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.006030000 probability, percentile 0.467490000 (date 2026-09-27)
Problem Types: CWE-94 | CWE-1336 | CWE-94 CWE-94: Improper Control of Generation of Code ('Code Injection') | CWE-1336 CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Getgrav | Grav | All | All | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta1 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta10 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta11 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta12 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta13 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta14 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta15 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta16 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta17 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta18 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta19 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta2 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta20 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta21 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta22 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta23 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta24 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta25 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta26 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta3 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta4 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta5 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta6 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta7 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta8 | All | All |
| Application | Getgrav | Grav | 1.8.0 | beta9 | All | All |
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/getgrav/grav/security/advisories/GHSA-gjc5-8cfh-653x | [email protected] | github.com | Exploit, Third Party Advisory |
| github.com/getgrav/grav/commit/e37259527d9c1deb6200f8967197a9fa587c6458 | [email protected] | github.com | Patch |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.