OpenBao allows cancellation of root rekey and recovery rekey operations without authentication

OpenBao exists to provide a software solution to manage, store, and distribute sensitive data including secrets, certificates, and keys. OpenBao before v2.3.0 allowed an attacker to perform unauthenticated, unaudited cancellation of root rekey and recovery rekey operations, effecting a denial of service. In OpenBao v2.2.0 and later, manually setting the configuration option `disable_unauthed_rekey_endpoints=true` allows an operator to deny these rarely-used endpoints on global listeners. A patch is available at commit fe75468822a22a88318c6079425357a02ae5b77b. In a future OpenBao release communicated on OpenBao's website, the maintainers will set this to `true` for all users and provide an authenticated alternative. As a workaround, if an active proxy or load balancer sits in front of OpenBao, an operator can deny requests to these endpoints from unauthorized IP ranges.