# CVE-2026-100522: Cotonti reflected cross-site scripting in message.php

Source: https://junglewise.ai/threats/cve-2026-100522-cotonti-through-1-0-0-contains-a-reflected-cross-site-scripting  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-26. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-100522 · Severity: medium · CVSS 6.1 · Published 2026-09-26

Cotonti is a PHP-based content management system. A reflected cross-site scripting vulnerability in its message.php file allows attackers to inject malicious JavaScript through the lng parameter. Unauthenticated attackers can craft malicious links to execute arbitrary JavaScript in a victim's browser, potentially stealing session cookies, credentials, or performing actions on behalf of the user.

Technologies: [Cotonti](https://junglewise.ai/threats/technologies/cotonti). Vendors: [Cotonti](https://junglewise.ai/threats/vendors/cotonti).

## Quick answers

**Is CVE-2026-100522 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100522 being exploited in the wild.

**How severe is CVE-2026-100522?** Medium severity, with a CVSS score of 6.1, published 26 September 2026.

**Which products and versions are affected?** Cotonti through 1.0.0.

**Is there a fix for CVE-2026-100522?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-100522 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-100522?** Check whether you run Cotonti at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A reflected XSS vulnerability exists in message.php where the lng parameter is not properly HTML-escaped before being output in a confirmation dialog. The vulnerability is exploitable via a crafted URL and requires no authentication or user interaction beyond clicking a malicious link. Attackers can execute arbitrary JavaScript in the victim's browser context to steal sensitive data or perform unauthorized actions.

## Affected products

- Cotonti Cotonti through 1.0.0

## Timeline

- 2026-09-26: disclosed

## References

- [https://github.com/Cotonti/Cotonti](https://github.com/Cotonti/Cotonti)
- [https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php](https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php)

## Related threats

- [Cotonti weak token generation in user registration](https://junglewise.ai/threats/cve-2026-121553-cotonti-through-1-0-0-generates-registration-and-email-change)
- [Cotonti cross-site request forgery in admin users](https://junglewise.ai/threats/cve-2026-101093-cotonti-through-1-0-0-contains-a-cross-site-request-forgery)
- [Cotonti cross-site request forgery in extensions manager](https://junglewise.ai/threats/cve-2026-100524-cotonti-through-1-0-0-contains-a-cross-site-request-forgery)
- [Cotonti open redirect in message.php](https://junglewise.ai/threats/cve-2026-100523-cotonti-through-1-0-0-contains-an-open-redirect-vulnerability-in)
- [Cotonti reflected cross-site scripting in search plugin](https://junglewise.ai/threats/cve-2026-100521-cotonti-through-1-0-0-contains-a-reflected-cross-site-scripting)