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FacturaScripts vulnerable to Reflected Cross-Site Scripting (XSS) via Cookie Manipulation

Low severity GitHub Reviewed Published May 7, 2026 in NeoRazorX/facturascripts • Updated May 7, 2026

Package

composer facturascripts/facturascripts (Composer)

Affected versions

<= 2025.71

Patched versions

None

Description

Summary

A Reflected Cross-Site Scripting (XSS) vulnerability exists in the fsNick cookie parameter. The application reflects the cookie's value directly into the HTML without sanitization.

Details

The fsNick cookie is rendered into the DOM without encoding. While the server does reject the modified session and forces a logout, the HTML containing the payload reaches the browser first. This lets the script execute immediately upon load, effectively beating the redirect.

PoC

  1. Log in to the application with any valid account.

image

  1. Capture any the GET request .

image

  1. Modify the value of "fsNick" with the following JavaScript:
    <script>alert(window.origin)</script>

  2. Send the modified request.

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  1. Result

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Impact

The payload executes before the session ends, which could potentially allow for a single unauthorized action before the logout.

References

@NeoRazorX NeoRazorX published to NeoRazorX/facturascripts May 7, 2026
Published to the GitHub Advisory Database May 7, 2026
Reviewed May 7, 2026
Last updated May 7, 2026

Severity

Low

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
Local
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
Low
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:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

EPSS score

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.

CVE ID

CVE-2026-27964

GHSA ID

GHSA-gq5c-rw37-g46c

Source code

Credits

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