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

Exp

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.

Published: 2025-12-01 Last update: 2025-12-03 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-66299 is rated High Exploit Risk (62.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.15%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2025-66299

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-66299

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-11 0.07% 0.15% +0.09%
2 2025-12-02 — 0.07% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-66299

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]

Weakness enumeration for CVE-2025-66299

GitHub Security Advisory for CVE-2025-66299

GHSA-gjc5-8cfh-653x · Severity: high · Ecosystem: composer — Grav is Vulnerable to Security Sandbox Bypass with SSTI (Server Side Template Injection)

Affected software / configurations for CVE-2025-66299

Vendor Product Version Raw CPE
getgrav grav < 1.8.0 cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta1:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta10:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta11:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta12:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta13:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta14:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta15:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta16:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta17:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta18:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta19:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta2:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta20:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta21:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta22:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta23:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta24:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta25:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta26:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta3:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta4:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta5:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta6:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta7:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta8:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta9:*:*:*:*:*:*

References for CVE-2025-66299

cvelogic Threat Intelligence