# CVE-2026-100521: Cotonti reflected cross-site scripting in search plugin

Source: https://junglewise.ai/threats/cve-2026-100521-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-2026-100521 · Severity: medium · CVSS 6.1 · Published 2026-09-26

Cotonti is a PHP content management framework used to build websites. The search plugin fails to sanitize user input in the highlight parameter, allowing attackers to inject malicious JavaScript that executes in the browsers of anyone clicking a crafted link, including site administrators. This could lead to session hijacking, credential theft, or administrative account takeover.

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

## Quick answers

**Is CVE-2026-100521 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-100521 being exploited in the wild.

**How severe is CVE-2026-100521?** 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-2026-100521?** 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-2026-100521 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-100521?** 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 cross-site scripting (XSS) vulnerability exists in the search plugin's highlight parameter where user input is directly embedded into JavaScript code without HTML or JavaScript escaping. An unauthenticated attacker can craft a malicious URL with JavaScript payload in the highlight parameter that executes in the victim's browser when visited. The vulnerability allows arbitrary JavaScript execution in the context of the vulnerable website.

## 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/plugins/search/search.header.php](https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.header.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 message.php](https://junglewise.ai/threats/cve-2026-100522-cotonti-through-1-0-0-contains-a-reflected-cross-site-scripting)