How severe is CVE-2025-66308?

No CVSS score has been assigned to CVE-2025-66308 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-66308?

CVE-2025-66308 affects the following packages: getgrav/grav (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2025-66308?

Update getgrav/grav to 1.8.0-beta.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-66308 is resolved across your whole dependency graph.

How do I detect CVE-2025-66308 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-66308 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2025-66308 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-66308 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-66308?

CVE-2025-66308 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 14th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-66308?

CVE-2025-66308 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-66308 published, and has it been updated?

CVE-2025-66308 was published on December 1, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2025-66308 — grav

Fix: getgrav/grav-plugin-admin@99f6532

CVE-2025-66308 is a Cross-site Scripting (XSS) vulnerability in getgrav/grav. A fix is available for getgrav/grav — see the affected versions and patch details below.

Grav Admin Plugin vulnerable to Cross-Site Scripting (XSS) Stored endpoint `/admin/config/site` parameter `data[taxonomies]`

Also known asGHSA-gqxx-248x-g29f

Published

Dec 1, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-66308.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs14th percentile — riskier than 14% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘getgrav/grav

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

A Stored Cross-Site Scripting (XSS) vulnerability was identified in the /admin/config/site endpoint of the Grav application. This vulnerability allows attackers to inject malicious scripts into the data[taxonomies] parameter. The injected payload is stored on the server and automatically executed in the browser of any user who accesses the affected site configuration, resulting in a persistent attack vector.

Details

Vulnerable Endpoint: POST /admin/config/site
Parameter: data[taxonomies]

The application does not properly validate or sanitize input in the data[taxonomies] field. As a result, an attacker can inject JavaScript code, which is stored in the site configuration and later rendered in the administrative interface or site output, causing automatic execution in the user's browser.

PoC

Payload:

"><script>alert('XSS-PoC')</script>

Steps to Reproduce:

Log in to the Grav Admin Panel with sufficient permissions to modify site configuration.
Navigate to Configuration > Site.
In the Taxonomies Types field (which maps to data[taxonomies]), insert the payload above:

"><script>alert('XSS-PoC')</script>
Save the configuration.

Go on Pages and click on one of them

The stored payload is executed immediately in the browser, confirming the Stored XSS vulnerability.

The HTTP request submitted during this process contains the vulnerable parameter and payload:

Impact

Stored XSS attacks can lead to severe consequences, including:

Session hijacking: Stealing cookies or authentication tokens to impersonate users
Credential theft: Harvesting usernames and passwords using malicious scripts
Malware delivery: Distributing unwanted or harmful code to victims
Privilege escalation: Compromising administrative users through persistent scripts
Data manipulation or defacement: Changing or disrupting site content
Reputation damage: Eroding trust among site users and administrators

Discoverer

Marcelo Queiroz

by CVE-Hunters

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`getgrav/grav`	all versions	1.8.0-beta.27`composer require getgrav/grav:^1.8.0-beta.27`

Affected Products

1 product · 1 configurations

Application

grav-plugin-admingetgrav

≤ 1.10.50

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update getgrav/grav to 1.8.0-beta.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-66308 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

## Summary A Stored Cross-Site Scripting (XSS) vulnerability was identified in the `/admin/config/site` endpoint of the _Grav_ application. This vulnerability allows attackers to inject malicious scripts into the `data[taxonomies]` parameter. The injected payload is stored on the server and automatically executed in the browser of any user who accesses the affected site configuration, resulting in a persistent attack vector. --- ## Details **Vulnerable Endpoint:** `POST /admin/config/site` **Parameter:** `data[taxonomies]` The application does not properly validate or sanitize input in

O3 Security · Impact-Aware SCA

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