November 5, 2025 -
2 minutes, 17 seconds
AMD confirms some Zen 5 CPUs have a worrying security flaw that could put users at risk — specifically a defect in the RDSEED instruction used for cryptographic random number generation. This flaw can cause non-random zero outputs, compromising cryptographic key integrity and potentially exposing sensitive data to attackers. Users and system administrators are now seeking answers on how this affects their systems and what AMD is doing to fix it.
The issue lies in AMD’s hardware-based random number generator (RNG) within the RDSEED instruction. When generating cryptographic keys, RDSEED may return zeroes instead of truly random values — a serious concern for encryption, digital signatures, and security tokens. This means attackers could theoretically reconstruct private keys, undermining data encryption and system protection on affected devices.
AMD has not disclosed an exact list of affected models but confirmed that certain processors built on the Zen 5 architecture are impacted. The flaw, labeled AMD-SB-7055, primarily affects 16-bit and 32-bit RDSEED operations. AMD advises developers and system admins to switch to 64-bit RDSEED or implement software-based randomness alternatives until a firmware update or patch becomes available.
AMD has acknowledged the problem and is working on mitigation strategies to restore the integrity of RDSEED-based cryptographic functions. The company recommends using software-based randomness libraries or updating system firmware once official patches roll out. Security experts advise immediate review of cryptographic systems relying on Zen 5 chips to prevent potential data exposure.
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