GHSA-mpjj-4688-3fxg
Grav vulnerable to Cross-Site Scripting (XSS) Stored endpoint `/admin/pages/[page]` in Multiples parameters
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
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Description
Summary
A Stored Cross-Site Scripting (XSS) vulnerability was identified in the /admin/pages/[page] endpoint of the Grav application. This vulnerability allows attackers to inject malicious scripts into the data[header][metadata], data[header][taxonomy][category], and data[header][taxonomy][tag] parameters. These scripts are stored in the page frontmatter and executed automatically whenever the affected page is accessed or rendered in the administrative interface.
Details
Vulnerable Endpoint: POST /admin/pages/[page]
Parameters:
-
data[header][metadata] -
data[header][taxonomy][category] -
data[header][taxonomy][tag]
The application fails to properly sanitize user input when saving page metadata or taxonomy fields via the Admin Panel. As a result, an attacker with access to the admin interface can inject a malicious script using these parameters, and the script will be stored in the page's YAML frontmatter. When the page or metadata is rendered (especially in the Admin Panel), the payload is executed in the browser of any user with access.
PoC
Payload:
<script>alert('PoC-XXS51')</script>
Steps to Reproduce:
-
Log into the Grav Admin Panel and navigate to Pages.
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Create or edit a page.
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Inject the payload above into any of the following fields in the Options tab:
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Metadata key name
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Category under Taxonomy
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Tag under Taxonomy
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- Save the page.
When the page is loaded again in the Admin Panel or potentially on the frontend (depending on how the metadata is used), the script is executed, confirming the Stored XSS vulnerability.
Impact
Stored XSS vulnerabilities can result in serious consequences, including:
-
Session hijacking: Attackers can steal authentication cookies or tokens
-
Malware delivery: Injected scripts can download malicious software
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Credential theft: Fake input fields can capture usernames and passwords
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Sensitive data exposure: Access to internal metadata and browser data
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Administrative access compromise: Especially dangerous in admin-facing interfaces
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Phishing attacks: Users can be redirected to external malicious sites
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Reputation damage: Executing arbitrary scripts in trusted systems undermines credibility
by CVE-Hunters
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getgrav/grav | all versions | 1.11.0-beta.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update getgrav/grav to 1.11.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mpjj-4688-3fxg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-mpjj-4688-3fxg is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-mpjj-4688-3fxg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-mpjj-4688-3fxg in your dependencies?
O3 detects GHSA-mpjj-4688-3fxg across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.