Grav is vulnerable to Server-Side Template Injection (SSTI) via Forms

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-66298: 0.40% estimated exploitation activity in the next 30 days; percentile 34.83 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Having a simple form on site can reveal the whole Grav configuration details (including plugin configuration details) by using the correct POST payload. Sensitive information may be contained in the configuration details. PoC Create a simple form with two fields, 'registration-number' and 'hp'. Add a submit button and set the method to POST(screenshot attached below). Form name set to 'hero-form'. Send a POST request with the following payload and you will notice a response with a php array listing the whole Grav configuration details - including plugins(screenshot attached). registration-number:d643aaaa hp:vJyifp form-name:hero-form uniqueformid:{{vardump(context|slice(0,7))}} Impact Server-Side Template (SST) vulnerability. The vulnerability affects the latest Grav version as of 25th of Match 2025 (1.7.48) with all plugins installed (including forms plugin v.7.4.2) to their latest versions as well.

Published by the source

2 Dec 2025, 01:25 UTC

Last modified by the source

2 Dec 2025, 01:25 UTC

Source last checked

26 Oct 2026, 14:35 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-8535-hvm8-2hmv

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# Patch Next advisory brief: CVE-2025-66298

Advisory: Grav is vulnerable to Server-Side Template Injection (SSTI) via Forms
IDs: CVE-2025-66298, GHSA-8535-hvm8-2hmv
Record: https://patchnext.com/advisories/cve-2025-66298 (revision 1, source checked 26 Oct 2026, 14:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: getgrav/grav 1.8.0-beta.27. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist getgrav/grav: affected < 1.8.0-beta.27; fixed in 1.8.0-beta.27

## Suggested inspection (read-only)
- Packagist getgrav/grav: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on getgrav/grav.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8535-hvm8-2hmv (GitHub-reviewed advisory GHSA-8535-hvm8-2hmv lists affected ranges: Packagist getgrav/grav >=0 <1.8.0-beta.27)

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