n8n before 1.123.83, 2.x before 2.41.4, and 2.42.x before 2.42.1 contains a stored cross-site scripting vulnerability in the Chat Trigger hosted-chat page, where insufficiently sanitised customCss values are interpolated into the page as markup. Workflow authors can publish a chat without n8n user authentication whose payload executes on the instance origin, acting on the sessions of signed-in visitors.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0