RDSEED Failure on AMD “Zen 5” Processors
Summary
AMD was notified of a bug in “Zen 5” processors that may cause the RDSEED instruction to return 0 at a rate inconsistent with randomness while incorrectly signaling success (CF=1), indicating a potential misclassification of failure as success. This issue was initially reported publicly via the Linux kernel mailing list and was not submitted through AMD’s Coordinated Vulnerability Disclosure (CVD) process.
AMD has determined that the 16-bit and 32-bit forms of the RDSEED instruction on “Zen 5” processors are affected. The 64-bit form of RDSEED is not affected. AMD plans to release mitigations for this vulnerability. Please see the details below.
CVE Details
| CVE | CVE Description | CVSS Score |
| CVE-2025-62626 | Improper handling of insufficient entropy in the AMD CPUs could allow a local attacker to influence the values returned by the RDSEED instruction, potentially resulting in the consumption of insufficiently random values. | 7.2 (High) CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
Affected Products and Mitigation
AMD plans to release mitigations to the Original Equipment Manufacturers (OEM) on the target dates listed below. Please contact your OEM for the BIOS update specific to your product(s).
AMD EPYC™ Series Processors
| Product | Mitigation Option 1 (AGESA) | Mitigation Option 2 (µcode) | ||
| AGESA | Mitigation Release Date | µcode | Mitigation Release Date | |
| AMD EPYC™ 9005 Series Processors | TurinPI 1.0.0.8 | Target release 2025-11-14 | Turin C1 : 0x0B00215A Turin Dense B0: 0x0B101054 | Target release late Oct’25 |
AMD Ryzen™ Series Processors
| Product | Mitigation | Mitigation Release Date |
| AMD Ryzen™ 9000 Series Desktop Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ 9000HX Series Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ AI 300 Series Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ AI Z2 Series Processors Extreme | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ AI Max 300 Series Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ Threadripper™ 9000 Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ Threadripper™ PRO 9000 WX-Series Processors | Version TBD | Target release late Nov’25 |
| AMD Ryzen™ Z2 Series Processors Extreme | Version TBD | Target release late Nov’25 |
AMD EPYC™ Embedded Series Processors
| Product | Mitigation | Mitigation Release Date |
| AMD EPYC™ Embedded 4005 Series Processors | Version TBD (PI) | Target release Jan'26 |
| AMD EPYC™ Embedded 9005 Series Processors | Version TBD (PI) | Target release 2025-11-14 |
| Version TBD (EDK2) | Target release 2025-11-14 |
AMD Ryzen™ Embedded Series Processors
| Product | Mitigation | Mitigation Release Date |
| AMD Ryzen™ Embedded 9000 Series Processors | Version TBD (PI) | Target release Jan'26 |
Revisions
| Revision Date | Description |
| 2025-10-23 | Initial publication |
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