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Hax CMS Stored Cross-Site Scripting vulnerability

High severity GitHub Reviewed Published Jun 9, 2025 in haxtheweb/issues • Updated Jun 9, 2025

Package

composer elmsln/haxcms (Composer)

Affected versions

< 11.0.0

Patched versions

11.0.0

Description

Summary

The application does not sufficiently sanitize user input, allowing for the execution of arbitrary JavaScript code. The 'saveNode' and 'saveManifest' endpoints take user input and store it in the JSON schema for the site. This content is then rendered in the generated HAX site.

Although the application does not allow users to supply a 'script' tag, it does allow the use of other HTML tags to run JavaScript.

Affected Resources

Impact

An authenticated attacker can use the site editor and settings editor to store malicious payloads in a HAX site which execute arbitrary JavaScript when a user visits the site. This can be used to steal a user's session cookie or other sensitive data.

PoCs

saveNode

To replicate this vulnerability, an attacker can use the "View Source" functionality within the site editor to enter a malicious payload.

  1. Select "View Source" within the HAX site editor and enter an XSS payload that does not use the "script" HTML tag.

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  1. Select "Update HTML" and observe the resulting alert.

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saveManifest

To exploit the 'SaveManifest' endpoint, an attacker can insert executable code into the URL field of the site settings editor: any payload added this way will execute when the site is loaded.

  1. Open the site settings editor.

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  1. Add JavaScript code to the URL field under the "Theme" header.

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  1. Reload the page to run the script.

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  1. The resulting page source will contain the script.

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References

@btopro btopro published to haxtheweb/issues Jun 9, 2025
Published to the GitHub Advisory Database Jun 9, 2025
Reviewed Jun 9, 2025
Published by the National Vulnerability Database Jun 9, 2025
Last updated Jun 9, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS score

CVE ID

CVE-2025-49137

GHSA ID

GHSA-2vc4-3hx7-v7v7

Source code

Credits

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