What’s Vulnerable › Vulnerabilities

CVE-2021-26318: Side-channels Related to the x86 PREFETCH Instruction

• Severity: medium (CVSS 4.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-13 · updated 2026-06-17
• Weakness: CWE-208

Description

A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information.

Affected products

• AMD Athlon Firmware: all versions
• AMD Athlon Pro Firmware: all versions
• AMD Epyc Firmware: all versions
• AMD Ryzen Firmware: all versions
• AMD Ryzen Pro Firmware: all versions

References

• https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017
• https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017

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