Overview
- AMD labeled the issue AMD-SB-7055 and said it affects Zen 5 processors across server and consumer lines, with 64-bit RDSEED remaining unaffected.
- Mitigations for EPYC 9005 servers are already deploying, and consumer firmware updates begin November 25 with additional releases planned through January 2026.
- AMD plans AGESA-based microcode to correct RDSEED behavior at the firmware level, to be distributed by OEMs and motherboard vendors.
- Linux kernel maintainers have disabled RDSEED on affected Zen 5 chips to prevent faulty entropy from being used until hardware fixes are in place.
- A Meta engineer first reported reproducible zero returns under stress testing, and AMD advises using the 64-bit instruction or software RNG fallbacks in the interim.