5.5

CVE-2021-26355: amd 3rd gen epyc Protection Mechanism Failure

CVSS: 5.5v3.1MediumModified
Published 10-01-2023Last modified 09-04-2025
Open JSON

Vulnerability summary

CVE-2021-26355 is a medium (CVSS 5.5) Protection Mechanism Failure vulnerability in amd 3rd gen epyc. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.17%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 10-01-2023
    PublishedVulnerability first disclosed.
  2. 09-04-2025
    Last modifiedVulnerability information updated.

Description

Insufficient fencing and checks in System Management Unit (SMU) may result in access to invalid message port registers that could result in a potential denial-of-service.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

0.00 pp

From 0.17% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.17%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Amd25 products

1 vendor · 25 products

References

1 links