CVE-2026-28509

LangBot has a Cross Site Scripting(XSS) Vulnerability

State: Published
Severity: 6.3 Medium
Published: Mar 6, 2026
Updated: Mar 6, 2026
Reserved: Feb 27, 2026

Description

LangBot is a global IM bot platform designed for LLMs. Prior to version 4.8.7, LangBot’s web UI renders user-supplied raw HTML using rehypeRaw, which can lead to a cross-site scripting (XSS) vulnerability. This issue has been patched in version 4.8.7.

Scores

CVSS	Score	Vector	Source
3.1	6.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
LangBotlangbot-app	< 4.8.7Affected

References

https://github.com/langbot-app/LangBot/security/advisories/GHSA-w8gq-g4pc-xh3h
https://github.com/langbot-app/LangBot/commit/614621ab7b84fe50da3c6137705cde5a99429866

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