AmoyLab Unla through 0.10.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to obtain valid access tokens because the OAuth2 server never authenticates a resource owner. Attackers can register a client, request a code from /authorize, and exchange it at /token to access OAuth2-protected MCP prefixes, proxied upstream APIs and injected credentials.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
amoylab:unla
References 5
https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/amoylab-unla-oauth-self-issued-token-…
NVD
https://github.com/AmoyLab/Unla/blob/v0.10.0/internal/auth/oauth.go#L86-L147
NVD
https://github.com/AmoyLab/Unla/blob/v0.10.0/internal/core/server.go#L229-L261
NVD
https://github.com/AmoyLab/Unla
NVD
https://www.vulncheck.com/advisories/amoylab-unla-through-0.10.0-oauth2-authent…
VulnCheck Advisory: AmoyLab Unla through 0.10.0 OAuth2 Authentication Bypass via /authorize