TI-2026-22771 Aliases CVE-2026-28509

LangBot has a Cross Site Scripting(XSS) Vulnerability

LOW 27CWE-79Published 2026-03-06 · Updated 2026-03-06

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Required
Attack complexity: Low
Impact type: Cross-site scripting
Confidentiality · integrity · availability: High · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00223 12th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed LangBot (langbot-app): 4.8.7

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
langbot-app	LangBot	before 4.8.7	4.8.7	Patch available	CNA

LangBot Vendorlangbot-app Affected before 4.8.7 Fixed in 4.8.7 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:langbot:langbot::::::::	before 4.8.7	Vulnerable	Langbot

cpe:2.3:a:langbot:langbot:*:*:*:*:*:*:*:* Versions before 4.8.7 Vulnerable ·Langbot

Remediation

Fix · CNA LangBot (langbot-app) Fixed in 4.8.7

Timeline

2026-10-02 Threatist record created from CVE-2026-28509

References

Exploit 1

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

Patch 1

https://github.com/langbot-app/LangBot/commit/614621ab7b84fe50da3c6137705cde5a99429866

TI-2026-61802 LangBot through 0.4.17 Unauthenticated Plugin Registration via WebSocket CVSS 4.0HIGH 8.8
TI-2026-61576 LangBot before 4.10.11 Authentication Bypass via Weak Recovery Key CVSS 4.0CRITICAL 9.2
TI-2025-37274 LangBot has a cross-directory file upload vulnerability, which could lead to system takeover CVSS 4.0HIGH 8.6
TI-2026-39312 LangBot: Authenticated RCE Via MCP Configuration CVSS 3.1HIGH 8.8
TI-2026-76465 Missing Lark/Feishu webhook authenticity check in LangBot CVSS 4.0HIGH 8.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences