Coder 2.38.0 before 2.38.4 Authorization Bypass via External Agent Credentials Endpoint

Coder 2.26.0 before 2.29.24, 2.30.0 before 2.34.16, 2.35.0 before 2.36.11, 2.37.0 before 2.37.8, and 2.38.0 before 2.38.4 contains an improper authorization flaw in the external agent credentials endpoint, which returns the workspace agent token to users with only workspace read access rather than ssh permission. Authenticated users with roles such as Template Admin or Organization Admin can use the token to read the owner's private Git SSH key and Git provider OAuth tokens, and impersonate the agent to receive the owner's sessions.