Security Sandbox Bypass with SSTI (Server Side Template Injection) in the Grav CMS
Priority HIGH 79CWE-1336Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-1336.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00652 51st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed grav (getgrav): 1.8.0-beta.27getgrav/grav (Packagist): 1.8.0-beta.27
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| getgrav | grav | before 1.8.0-beta.27 | 1.8.0-beta.27 | Patch available | CNA |
| — | getgrav/grav (Packagist) | before 1.8.0-beta.27 | 1.8.0-beta.27 | Patch available | GHSA-gjc5-8cfh-653x |
- grav Vendorgetgrav Affected before 1.8.0-beta.27 Fixed in 1.8.0-beta.27 Patch available CNA
- getgrav/grav (Packagist) Vendor— Affected before 1.8.0-beta.27 Fixed in 1.8.0-beta.27 Patch available GHSA-gjc5-8cfh-653x
CPE configurations NVD · 27
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:* | before 1.8.0 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta1:*:*:*:*:*:* | 1.8.0 beta1 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta10:*:*:*:*:*:* | 1.8.0 beta10 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta11:*:*:*:*:*:* | 1.8.0 beta11 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta12:*:*:*:*:*:* | 1.8.0 beta12 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta13:*:*:*:*:*:* | 1.8.0 beta13 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta14:*:*:*:*:*:* | 1.8.0 beta14 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta15:*:*:*:*:*:* | 1.8.0 beta15 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta16:*:*:*:*:*:* | 1.8.0 beta16 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta17:*:*:*:*:*:* | 1.8.0 beta17 | Vulnerable | getgrav |
- cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:* Versions before 1.8.0 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta1:*:*:*:*:*:* Versions 1.8.0 beta1 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta10:*:*:*:*:*:* Versions 1.8.0 beta10 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta11:*:*:*:*:*:* Versions 1.8.0 beta11 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta12:*:*:*:*:*:* Versions 1.8.0 beta12 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta13:*:*:*:*:*:* Versions 1.8.0 beta13 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta14:*:*:*:*:*:* Versions 1.8.0 beta14 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta15:*:*:*:*:*:* Versions 1.8.0 beta15 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta16:*:*:*:*:*:* Versions 1.8.0 beta16 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta17:*:*:*:*:*:* Versions 1.8.0 beta17 Vulnerable ·getgrav
Show 17 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:getgrav:grav:1.8.0:beta18:*:*:*:*:*:* | 1.8.0 beta18 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta19:*:*:*:*:*:* | 1.8.0 beta19 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta2:*:*:*:*:*:* | 1.8.0 beta2 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta20:*:*:*:*:*:* | 1.8.0 beta20 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta21:*:*:*:*:*:* | 1.8.0 beta21 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta22:*:*:*:*:*:* | 1.8.0 beta22 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta23:*:*:*:*:*:* | 1.8.0 beta23 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta24:*:*:*:*:*:* | 1.8.0 beta24 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta25:*:*:*:*:*:* | 1.8.0 beta25 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta26:*:*:*:*:*:* | 1.8.0 beta26 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta3:*:*:*:*:*:* | 1.8.0 beta3 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta4:*:*:*:*:*:* | 1.8.0 beta4 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta5:*:*:*:*:*:* | 1.8.0 beta5 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta6:*:*:*:*:*:* | 1.8.0 beta6 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta7:*:*:*:*:*:* | 1.8.0 beta7 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta8:*:*:*:*:*:* | 1.8.0 beta8 | Vulnerable | getgrav |
| cpe:2.3:a:getgrav:grav:1.8.0:beta9:*:*:*:*:*:* | 1.8.0 beta9 | Vulnerable | getgrav |
- cpe:2.3:a:getgrav:grav:1.8.0:beta18:*:*:*:*:*:* Versions 1.8.0 beta18 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta19:*:*:*:*:*:* Versions 1.8.0 beta19 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta2:*:*:*:*:*:* Versions 1.8.0 beta2 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta20:*:*:*:*:*:* Versions 1.8.0 beta20 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta21:*:*:*:*:*:* Versions 1.8.0 beta21 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta22:*:*:*:*:*:* Versions 1.8.0 beta22 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta23:*:*:*:*:*:* Versions 1.8.0 beta23 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta24:*:*:*:*:*:* Versions 1.8.0 beta24 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta25:*:*:*:*:*:* Versions 1.8.0 beta25 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta26:*:*:*:*:*:* Versions 1.8.0 beta26 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta3:*:*:*:*:*:* Versions 1.8.0 beta3 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta4:*:*:*:*:*:* Versions 1.8.0 beta4 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta5:*:*:*:*:*:* Versions 1.8.0 beta5 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta6:*:*:*:*:*:* Versions 1.8.0 beta6 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta7:*:*:*:*:*:* Versions 1.8.0 beta7 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta8:*:*:*:*:*:* Versions 1.8.0 beta8 Vulnerable ·getgrav
- cpe:2.3:a:getgrav:grav:1.8.0:beta9:*:*:*:*:*:* Versions 1.8.0 beta9 Vulnerable ·getgrav
Remediation
- Fix · CNA grav (getgrav) Fixed in 1.8.0-beta.27
- Fix · GHSA-gjc5-8cfh-653x getgrav/grav (Packagist) Fixed in 1.8.0-beta.27 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-66299
- 2026-10-03 Alias added: GHSA-gjc5-8cfh-653x
- 2026-11-01 EPSS moved to the 50th–90th percentile
References
More getgrav Grav vulnerabilities
- TI-2025-28971 Cross Site Scripting vulnerability in grav v.1.7.48 and before allows an attacker to… CVSS 3.1CRITICAL 9.8
- TI-2021-22428 GravCMS 1.10.7 - Arbitrary YAML Write/Update (Unauthenticated) (2) CVSS 4.0CRITICAL 9.3
- TI-2025-41064 In grav <1.7.49.5, a SSRF (Server-Side Request Forgery) vector may be triggered via Twig… CVSS 3.1CRITICAL 9.1
- TI-2026-30888 Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component. CVSS 4.0HIGH 8.8
- TI-2025-40768 Grav is vulnerable to RCE via SSTI through Twig Sandbox Bypass CVSS 4.0HIGH 8.7
- TI-2023-17087 Grav Server-side Template Injection via Insufficient Validation in filterFilter CVSS 3.1HIGH 8.8
Sources
- CVE-2025-66299 · CVE Program
- CVE-2025-66299 · NVD
- FIRST EPSS
- GHSA-gjc5-8cfh-653x · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences