Gogs is an open source self-hosted Git service. Prior to 0.14.3, when ENABLE_REVERSE_PROXY_AUTHENTICATION is enabled, Gogs accepts the configured authentication header (default: X-WEBAUTH-USER) directly from client requests without validating that the request originated from a trusted reverse proxy. Any remote attacker who can reach the Gogs service can forge this header to impersonate any user or trigger automatic account creation, completely bypassing authentication. This vulnerability is fixed in 0.14.3.