VulnerabilityPublished 24 Jan 2026Updated 26 Jan 2026

CVE-2026-24399: chattermate.chat · Cross-site Scripting

Affects chattermate.chatSource CVE Database V5

Not known to be exploited · CVSS 9.3 Critical : upgrade to 1.0.9 as a priority.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

9.3Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.0.9

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade chattermate.chat and chattermate/chattermate.chat to 1.0.9.

Affected software

Product	Affected	Fixed in
chattermatechattermate.chat	Affected <1.0.9	Fixed in 1.0.9
GitHubchattermate/chattermate.chat`pkg:github/chattermate/chattermate.chat`Other threats	Affected <1.0.9	Fixed in 1.0.9

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Immediate upgrade to chattermate.chat version 1.0.9 or later, where the vulnerability is fixed.
Implement strict input validation and output encoding on all user-supplied content, especially chat inputs, to prevent injection of malicious HTML or JavaScript.
Employ Content Security Policy (CSP) headers to restrict execution of unauthorized scripts and iframe sources.
Conduct user awareness training to recognize and avoid interacting with suspicious chat inputs or links.
Monitor chat logs and user activity for signs of exploitation or anomalous behavior.
Use web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting chattermate.chat.
Regularly audit and test chatbot implementations for security weaknesses, including penetration testing focused on injection flaws.
Isolate chatbot services from critical internal systems to limit potential lateral movement if compromised.

Description

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.

Impact

For European organizations, this vulnerability can lead to severe data breaches involving theft of session tokens and cookies, enabling attackers to impersonate users and gain unauthorized access to sensitive information or internal systems. Organizations relying on chattermate.chat for customer interaction or internal AI chatbot services risk exposure of confidential client data and internal communications. The compromise of user sessions can facilitate lateral movement within networks, leading to broader security incidents. Additionally, the reputational damage and regulatory consequences under GDPR for failing to protect personal data could be substantial. The attack vector requires user interaction, which may be exploited through social engineering or phishing campaigns targeting employees or customers. Given the critical severity and ease of exploitation, organizations must prioritize remediation to prevent potential exploitation and data loss.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 31 Jan 2026, 08:53 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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