Grav vulnerable to Cross-Site Scripting (XSS) Stored endpoint `/admin/pages/[page]` parameter `data[header][template]` in Advanced Tab
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][template] parameter. The script is saved within the page's frontmatter and executed automatically whenever the affected content is rendered in the administrative interface or frontend view.
Details
Vulnerable Endpoint: POST /admin/pages/[page]
Parameter: data[header][template]
The application fails to properly sanitize user input in the data[header][template] field, which is stored in the YAML frontmatter of the page. An attacker can inject JavaScript code using this field, and the payload is rendered and executed when the page is accessed, especially within the Admin Panel interface.
PoC
Payload:
<script>alert('PoC-XXS73')</script>
Steps to Reproduce:
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Log in to the Grav Admin Panel and navigate to Pages.
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Create a new page or edit an existing one.
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In the Advanced > Template field (which maps to
data[header][template]), insert the payload: -
Save the page.
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Return to the Pages section and click on the three-dot menu of the affected page:
-
The stored XSS payload is triggered, and the script is executed in the browser:
Impact
Stored XSS vulnerabilities can have serious consequences, including:
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Session hijacking: Capturing admin session cookies or tokens
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Malware delivery: Executing scripts that load malicious resources
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Credential theft: Creating fake login prompts to steal usernames/passwords
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Data exposure: Reading sensitive metadata or page contents
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Privilege escalation: Performing actions as an authenticated user
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Website defacement: Altering visual or functional elements of the site
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Reputation damage: Undermining user trust in the application
by CVE-Hunters
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | getgrav/grav | < 1.8.0-beta.27 | 1.8.0-beta.27 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:L/VI:L/VA:N/SC:H/SI:H/SA:H- Weakness (CWE)
CWE-79- Platform
- Composer
- Package
getgrav/grav- Disclosed
- 02.12.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-7g78-5g5g-mvfj - CC BY 4.0
Vulnerability history: getgrav/grav
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 99
- First → latest
- 11.2019 09.2026
- Without a fix
- 6
- Exploited in attacks
- 0
Severity breakdown
- Critical 7
- High 47
- Medium 41
- Low 4
Disclosures per year
- 2019: 1
- 2020: 1
- 2021: 4
- 2022: 10
- 2023: 5
- 2024: 8
- 2025: 23
- 2026: 47
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Grav vulnerable to Cross-Site Scripting (XSS) Stored endpoint `/admin/pages/[page]` parameter `data[header][template]` in Advanced Tab this entry
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