vulnerability / NVI-00003786 / Revision 3
Grav is vulnerable to RCE via SSTI through Twig Sandbox Bypass
OSV carries this publisher advisory for getgrav/grav. This is an aggregated source copy; consult the original publisher and compare update dates.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
3.019%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.87446. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
getgrav/grav
source listedECOSYSTEM: introduced 0; fixed 1.8.0-beta.27
### Summary A Server-Side Template Injection (SSTI) vulnerability exists in Grav that allows authenticated attackers with editor permissions to execute arbitrary commands on the server and, under certain conditions, may also be exploited by unauthenticated attackers. This vulnerability stems from weak regex validation in the `cleanDangerousTwig` method. ### Important - First of all this vulnerability is due to weak sanitization in the method `clearDangerousTwig`, so any other class that calls it indirectly through for example `$twig->processString` to sanitize code is also vulnerable. - For this report, we will need the official Form and Admin plugin installed, also I will be chaining this with another vulnerability to allow an editor which is a user with only pages permissions to edit the process section of a form. - I made another report for the other vulnerability which is a Broken Access Control which allows a user with full permission for pages to change the process section by intercepting the request and modifying it. ### Permissions Needed - The main case for this vulnerability is an editor which can unconditionally takeover the whole system through creating a vulnerable
03 / Response
What to do next
- vendor patch
The original advisory lists fixed boundaries 1.8.0-beta.27 for getgrav/grav. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-662m-56v4-3r8f ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2025-66294 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.