NotChatbot WebChat has a stored cross-site scripting (XSS) vulnerability

Description

A stored cross-site scripting (XSS) vulnerability exists in the NotChatbot WebChat widget thru 1.4.4. User-supplied input is not properly sanitized before being stored and rendered in the chat conversation history. This allows an attacker to inject arbitrary JavaScript code which is executed when the chat history is reloaded. The issue is reproducible across multiple independent implementations of the widget, indicating that the vulnerability resides in the product itself rather than in a specific website configuration.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Source code
Not specified
Published (advisory)
2026-03-18 18:31:18 UTC
Updated
2026-03-19 12:50:47 UTC
GitHub reviewed
2026-03-19 12:50:46 UTC
NVD published
2026-03-18

EPSS Score

Score Percentile
0.03% 8.74%

CVSS Scores

Base score Version Severity Vector
5.3 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:L)
Limited confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:L)
Limited integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm @developer.notchatbot/webchat <= 1.5.0

References

cvelogic Threat Intelligence