What is the CVSS score of CVE-2026-24399?

CVE-2026-24399 has a CVSS 3.1 base score of 9.3 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2026-24399?

Yes, a public proof-of-concept exploit is available for CVE-2026-24399. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-24399?

Within 24 hours: Identify all ChatterMate deployments and their versions; disable public-facing ChatterMate instances if running vulnerable versions. Within 7 days: Apply vendor patches to all affected systems and validate remediation in staging environments. Within 30 days: Conduct security audit of patched systems, review chat logs for exploitation attempts, and implement input validation monitoring.

Chattermate CVE-2026-24399

CRITICAL

Cross-site Scripting (XSS) (CWE-79)

2026-01-24 security-advisories@github.com

XSS AI / ML Chattermate

9.3

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Craft malicious iframe with javascript: URI
Exploit

Submit payload via chat input
Execution

Browser executes injected script
Impact

Steal localStorage tokens and cookies

Vulnerability Assessment

Weakness	CWE CWE-79 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output encoding, context-aware escaping MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	ChatterMate versions 1.0.8 and below with HTML/JavaScript input processing enabled. Attacker requires user interaction (UI:R) to click or interact with chatbot interface. No authentication required for chat input submission.
Impact	CVSS 9.3. AI chatbot XSS could affect other users viewing chat histories or admin dashboards.
Exploit ScenarioDerived	User submits message with JavaScript payload to chatbot, which persists and executes in admin's browser when reviewing conversations.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.

Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Stored XSS in ChatterMate AI chatbot framework versions 1.0.8 and below. The chatbot accepts and renders malicious HTML/JavaScript from user input. PoC and patch available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:59 CVSS 9.3

XSS via chatbot input in ChatterMate.

RemediationAI

Update to patched version.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

CWE-79 in ChatterMate chatbot. User messages containing JavaScript are stored and rendered without sanitization.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 9.3 CRITICAL

AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Lifecycle Timeline

PoC Detected

Feb 12, 2026 - 16:05 vuln.today

Public exploit code

Patch released

Feb 12, 2026 - 16:05 nvd

Patch available

CVE Published

Jan 24, 2026 - 01:15 nvd

CRITICAL 9.3

DescriptionGitHub Advisory

ChatterMate is a no-code AI chatbot agent framework. In versions 1.0.8 and below, the chatbot accepts and executes malicious HTML/JavaScript payloads when supplied as chat input. Specifically, an <iframe> payload containing a javascript: URI can be processed and executed in the browser context. This allows access to sensitive client-side data such as localStorage tokens and cookies, resulting in client-side injection. This issue has been fixed in version 1.0.9.

Executive ViewAI

Why It Matters

ChatterMate chatbot instances running versions 1.0.8 and below are vulnerable to arbitrary code execution through malicious chat inputs, allowing attackers to compromise customer data, deploy malware, or manipulate bot responses. This critical vulnerability poses an immediate risk to any organization using ChatterMate for customer-facing applications or internal operations.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not possible: implement Web Application Firewall (WAF) rules to block HTML/JavaScript payloads in chat inputs; restrict ChatterMate access to internal networks only; disable ChatterMate service until patching is complete; implement strict Content Security Policy (CSP) headers; enable verbose logging and real-time alerting for suspicious chat patterns.

Threat Intelligence Overview

EPSS Score

0.0%

Top 98% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available Yes

Active threat No

Deciding rule

CRITICAL severity + public POC available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.