CVE-2026-91921CWE-79cross-site-scripting

CVE-2026-91921

published September 21, 2026

CVSS
5.1
EPSS
1%
Percentile
47.9
In the wild
Unconfirmed
What it is

Cross-Site Scripting (XSS) vulnerability due to inadequate input sanitisation in the client-side rendering engine of the 1millionbot AI Chat Platform. An unauthenticated remote user could cause external hyperlinks to be rendered in the web interface by sending messages containing Markdown syntax and certain unsanitised content blocks. The impact is limited to the user’s own interactive session; no compromise of internal infrastructure, access to third-party data or impact on administrative panels has been identified.

The record
Technical detail
CVSS
5.1 · NONE
CVSS v4.0
5.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
EPSS
0.00596 · 47.9th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-09-21T14:17Z
References (1)
EPSS history
Timeline
  • 23 SEP 03:49Z
    EPSS moved — → 0%
    epss
  • 21 SEP 09:43Z
    Cross-Site Scripting (XSS) in 1millionbot’s AI chatbot platform
    cvelistv5