The pdnsd is a database name server daemon used by the IBM AIX C Set ++ compiler. It's a relatively niche software, and if you don't recognize the name, you're probably not affected. The pdnsd is responsible for resolving names in the operating system.
You're affected if you use IBM AIX version 5.2 or earlier, which includes the pdnsd daemon. Check with your IT department to see if your AIX systems are still running this software.
Contact IBM directly for a patched version - there's no public patch link in the advisory.
Immediate mitigations:
- Restrict network access to your pdnsd instance (firewall it from the public internet)
- Audit system logs for suspicious activity related to the pdnsd daemon