CVE-2026-24399Public exploitNetwork attack vector

Stored XSS via incomplete chat-input sanitization

Published Jan 24, 2026 · Updated Jan 24, 2026

Stored XSS in ChatterMate 1.0.8 and earlier allows remote attackers to execute JavaScript in an agent's browser through chat input. The WidgetBuilder renderMarkdown path and the agent inbox and preview renderers fail to remove a javascript: iframe payload before browser rendering. No authentication is required, but an agent must view the stored message; execution can read cookies and localStorage tokens or alter the active session.

CVSS severity9.3
Critical
EPSS probability0.31%
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 ChatterMate 1.0.8 and earlier allows remote attackers to execute JavaScript in an agent's browser through chat input. The WidgetBuilder renderMarkdown path and the agent inbox and preview renderers fail to remove a javascript: iframe payload before browser rendering. No authentication is required, but an agent must view the stored message; execution can read cookies and localStorage tokens or alter the active session.

The record

CVE
CVE-2026-24399
Published
Jan 24, 2026
Updated
Jan 24, 2026
Vendor
ChatterMate AI Limited
Product
ChatterMate
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 24, 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=< 1.0.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ChatterMate AI Limited · ChatterMateversion=< 1.0.9

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
9.3GitHub CNACVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
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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