Cross-Site Scripting Vulnerability in LangBot IM Bot Platform
CVE-2026-28509

6.3MEDIUM

Key Information:

Vendor

Langbot-app

Status
Langbot
Vendor
CVE Published:
6 March 2026

What is CVE-2026-28509?

LangBot, a global instant messaging bot platform designed for large language models, was found to have a cross-site scripting (XSS) vulnerability in its web UI. This vulnerability occurs because the application improperly renders user-supplied raw HTML before processing. Versions prior to 4.8.7 are susceptible to this risk, allowing attackers to potentially execute arbitrary scripts in the context of users' sessions. Users are recommended to upgrade to version 4.8.7 or later to mitigate this issue.

Affected Version(s)

LangBot < 4.8.7

References

https://github.com/langbot-app/LangBot/security/advisorie...
x_refsource_CONFIRM
https://github.com/langbot-app/LangBot/commit/614621ab7b8...
x_refsource_MISC

CVSS V3.1

Score:
6.3
Severity:
MEDIUM
Confidentiality:
High
Integrity:
Low
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.