How severe is CVE-2025-66309?

No CVSS score has been assigned to CVE-2025-66309 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-66309?

CVE-2025-66309 affects the following packages: getgrav/grav (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2025-66309?

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-2025-66309 is resolved across your whole dependency graph.

How do I detect CVE-2025-66309 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-2025-66309 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-2025-66309 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-66309 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-2025-66309?

CVE-2025-66309 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 16th 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-2025-66309?

CVE-2025-66309 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-2025-66309 published, and has it been updated?

CVE-2025-66309 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-2025-66309 — grav

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

CVE-2025-66309 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 vulnerable to Cross-Site Scripting (XSS) Reflected endpoint /admin/pages/[page], parameter data[header][content][items], located in the "Blog Config" tab

Also known asGHSA-65mj-f7p4-wggq

Published

Dec 1, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 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-2025-66309.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs16th percentile — riskier than 16% 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 Reflected 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][content][items] parameter.

Details

Vulnerable Endpoint: GET /admin/pages/[page]
Parameter: data[header][content][items]

The application fails to properly validate and sanitize user input in the data[header][content][items] parameter. As a result, attackers can craft a malicious URL with an XSS payload. When this URL is accessed, the injected script is reflected back in the HTTP response and executed within the context of the victim's browser session.

PoC

Payload:

"><ImG sRc=x OnErRoR=alert('XSS-PoC3')>

Log in to the Grav Admin Panel and navigate to Pages.
Create a new page or edit an existing one.
In the Advanced > Blog Config > Items field (which maps to data[header][content][items]), insert the payload above.

Save the page.
The malicious payload is reflected and rendered by the application without proper sanitization. The JavaScript code is immediately executed in the browser.

Impact

Reflected cross-site scripting (XSS) attacks can have serious consequences, including:

User actions: Attackers can perform actions on behalf of the user
Data theft: Sensitive information such as session cookies can be stolen
Account compromise: Attackers may impersonate legitimate users
Malicious code execution: Arbitrary JavaScript code can run in the user’s browser
Website defacement or misinformation: Malicious output may be injected visually
User redirection: Victims may be redirected to phishing or malicious websites

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-2025-66309 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 Reflected 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][content][items]` parameter. --- ## Details **Vulnerable Endpoint:** `GET /admin/pages/[page]` **Parameter:** `data[header][content][items]` The application fails to properly validate and sanitize user input in the `data[header][content][items]` parameter. As a result, attackers can craft a malicious URL with an XSS payload. When this URL is accessed, the injec

O3 Security · Impact-Aware SCA

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