CVE-2026-90474

MCPHub before 1.0.32 ships an embedded OAuth 2.0 authorization server in which client authentication is disabled by default and PKCE enforcement is only optional. As a result, an attacker who manages to obtain a victim's authorization code — for example by intercepting it in transit — can redeem that code at the token endpoint without presenting a client secret or PKCE verifier. Successful redemption yields access tokens that grant the attacker access to the victim's MCPHub account and all of its privileges. Any operator running an affected version is exposed, with risk highest where the MCPHub interface is reachable over untrusted networks or unencrypted connections. There is currently no CISA KEV listing, no public proof-of-concept, and no confirmed exploitation in the wild.

What to do: Upgrade MCPHub to version 1.0.32 or later. Where immediate patching is not possible, enable client authentication (require client secrets) and enforce PKCE on the embedded OAuth authorization server, and avoid exposing MCPHub over plain HTTP or to untrusted networks. Review token-issuance and authorization-code redemption logs for unexpected redemptions that could indicate intercepted codes being exchanged.