Cal.com (calcom/cal.diy) versions through 4.7.15 contain a stored cross-site scripting vulnerability. The single booking view (e.g., https://app.cal.com/booking/<id>) renders booking-question field labels via React's dangerouslySetInnerHTML without sanitizing or escaping user input. An attacker who can create an event type with a malicious booking-question label can inject arbitrary HTML/JavaScript that executes when a victim opens the crafted booking URL.
The issue is fixed in v4.7.16.
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
High
Complete data modification
Availability
Low
Partial disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 3
https://github.com/calcom/cal.diy/commit/00689fda0a30b8f933c096f02c1fe092a4206d…
disclosure@vulncheck.com
https://github.com/calcom/cal.diy/security/advisories/GHSA-vgj7-76cw-h6f8
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/cal-com-through-cross-site-scripting-via-b…
disclosure@vulncheck.com