Executive brief
Kong API Gateway Enterprise contains a JWT validation vulnerability in its OAuth2 and DataKit integration components that fails to properly validate JWT signing algorithms. An unauthenticated attacker can craft a forged JWT token that bypasses authentication checks, potentially allowing unauthorized access to APIs and data protected by the gateway.
Technical details
This is a JWT algorithm confusion / signature verification vulnerability affecting Kong's MCP OAuth2 and DataKit integrations. The vulnerable code does not properly validate that the JWT signing algorithm matches the type of key used for verification, a classic JWT bypass technique. An unauthenticated remote attacker can craft a malicious JWT token that is incorrectly accepted as valid, leading to authentication bypass. The vulnerability allows potential compromise of confidentiality, integrity, and availability. Patch availability should be checked against Kong's official changelog and security advisories.
Affected products
- Kong API Gateway Enterprise <UNKNOWN>
Timeline
- 2026-09-16: disclosed