CVE-2026-101916: @grpc/grpc-js: In certain configurations, getAuthContext can return unauthorized certificates as though they were authorized

When server credentials are created with the requireClientCertificate option set to false, getAuthContext does not distinguish between authorized and unauthorized certificates in its return value. This can create improper authentication vulnerabilities for @grpc/grpc-js users who use the result of getAuthContext for authentication.

In particular, @grpc/grpc-js-xds can both set the requireClientCertificate option to false and use the return value of getAuthContext for RBAC authentication in some configurations.