Impact
Users can either intentionally or inadvertently create a keyspace containing / characters such that from that point on, anyone who tries to view keyspaces from VTAdmin will receive an error. Trying to list all the keyspaces using vtctldclient GetKeyspaces will also return an error.
Note that all other keyspaces can still be administered using the CLI (vtctldclient).
Patches
v16.0.1 (corresponding to 0.16.1 on pkg.go.dev)
Workarounds
Delete the offending keyspace using a CLI client (vtctldclient)
vtctldclient --server ... DeleteKeyspace a/b
Found during a security audit sponsored by the CNCF and facilitated by OSTIF.