@zereight/mcp-gitlab version prior to 2.1.30 contains multiple security flaws that bypass key safety controls such as read-only mode, project allow-list, and transport authentication. These include a GraphQL mutation bypass that allows unauthorized writes, unauthenticated access to HTTP and SSE transports, a session exhaustion denial-of-service, and exposure of CI job traces that can be manipulated by attackers. These vulnerabilities enable attackers with access to the MCP server port or a semi-trusted client to perform unauthorized GitLab writes, access GitLab credentials without authentication, and cause denial of service.