CVE-2026-28509Public exploitNetwork attack vector

Credential theft via unsanitized raw HTML rendering

Published Mar 6, 2026 · Updated Mar 6, 2026

Stored XSS in LangBot before 4.8.7 allows remote authenticated users to steal session tokens and API credentials through the web UI. PluginReadme.tsx, DebugDialog.tsx, and the release-note dialog pass untrusted Markdown to ReactMarkdown with rehypeRaw but no sanitization, permitting embedded HTML to execute script. Exploitation requires a victim to view a crafted plugin README, debug-chat message, or release note, and the resulting script runs with that victim's browser session.

CVSS severity6.3
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in LangBot before 4.8.7 allows remote authenticated users to steal session tokens and API credentials through the web UI. PluginReadme.tsx, DebugDialog.tsx, and the release-note dialog pass untrusted Markdown to ReactMarkdown with rehypeRaw but no sanitization, permitting embedded HTML to execute script. Exploitation requires a victim to view a crafted plugin README, debug-chat message, or release note, and the resulting script runs with that victim's browser session.

The record

CVE
CVE-2026-28509
Published
Mar 6, 2026
Updated
Mar 6, 2026
Vendor
LangBot
Product
LangBot
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.8.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LangBot · LangBotversion=< 4.8.7

Published CVSS scores

6.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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