XSS in Chattermate
CVE-2026-24399
ChatterMate is a no-code AI chatbot agent framework. In versions 1.0.8 and below, the chatbot accepts and executes malicious HTML/JavaScript payloads when supplied as chat input. Specifically, an <iframe> payload containing a javascript: URI can be processed and executed in the browser context. This allows access to sensitive client-side data such as localStorage tokens and cookies, resulting in client-side injection. This issue has been fixed in version 1.0.9.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.003 (22.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.
Affected products
- Chattermate
- Chattermate Chattermate.chat — versions < 1.0.9
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-24399?
- CVE-2026-24399 is a critical-severity vulnerability in Chattermate, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-01-24.
- How severe is CVE-2026-24399?
- Critical severity. CVSS v3 base score is 9.3 out of 10.