A flaw was found in rpcbind. This vulnerability allows a remote, unauthenticated attacker to cause a Denial of Service (DoS) by sending a large number of unique requests. The rpcbind service records previously unseen RPC (Remote Procedure Call) statistics in unbounded in-memory lists, leading to persistent memory growth and increased CPU usage. This can degrade or exhaust service availability.
Restrict network access to the rpcbind service on port 111 to trusted systems. This can be achieved by configuring firewall rules to limit inbound connections. For example, using firewalld on Red Hat Enterprise Linux:
```bash
<h1>To allow access only from a specific trusted network (e.g., 192.168.1.0/24)</h1>
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" port port="111" protocol="tcp" accept'
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" port port="111" protocol="udp" accept'
firewall-cmd --reload
```
If rpcbind is only required for local services, ensure it is configured to listen only on the loopback interface or is otherwise protected from external network exposure. Applying these firewall rules will take effect immediately upon firewall-cmd --reload and may temporarily interrupt existing connections to rpcbind.