Medium 6.3Published Mar 5, 2026

CVE-2026-28509LangBot has a Cross Site Scripting(XSS) Vulnerability

Updated under an hour ago (Oct 27, 2026, 1:50 PM ET)

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It affects langbot-app LangBot and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for langbot-app LangBot

Exploited in the last 30 days

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.

CVSS: 6.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Mar 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

langbot-app LangBot langbot_app:langbot (from the name)	before 4.8.7	CNA record
langbot langbot langbot:langbot	before 4.8.7	NVD

References

References

https://github.com/langbot-app/LangBot/security/advisories/GHSA-w8gq-g4pc-xh3h	x-refsource-confirm, exploit, vendor-advisory
https://github.com/langbot-app/LangBot/commit/614621ab7b84fe50da3c6137705cde5a99429866	x-refsource-misc, patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.