How severe is CVE-2021-26318?

CVE-2021-26318 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-26318 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26318?

CVE-2021-26318 primarily affects Amd Athlon Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26318?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-26318 published?

CVE-2021-26318 was published on 2021-10-13 and last updated on 2026-06-17.

CVE-2021-26318

CVE-2021-26318 is a medium-severity vulnerability in Amd Athlon Firmware with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-203.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
CVSS v2: 1.9
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Amd Athlon Firmware
Published: 2021-10-13
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-26318?: 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.
How severe is CVE-2021-26318?: CVE-2021-26318 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-26318 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26318?: CVE-2021-26318 primarily affects Amd Athlon Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26318?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26318 published?: CVE-2021-26318 was published on 2021-10-13 and last updated on 2026-06-17.

References

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

Affected products (5)

cpe:2.3:o:amd:athlon_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:amd:athlon_pro_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:amd:ryzen_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:amd:ryzen_pro_firmware:-:*:*:*:*:*:*:*

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