CVE-2021-20487

Name: CVE-2021-20487
Creator: NVD / NIST
Published: 2021-05-26T17:15:14.26+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 0.68%

Last modified Jun 17, 2026

CVE-2021-20487 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. IBM Power9 Self Boot Engine(SBE) could allow a privileged user to inject malicious code and compromise the integrity of the host firmware bypassing the host firmware signature verification process.. EPSS estimates a 0.68% chance of exploitation in the next 30 days.

Description

IBM Power9 Self Boot Engine(SBE) could allow a privileged user to inject malicious code and compromise the integrity of the host firmware bypassing the host firmware signature verification process.

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

0.68%

47.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Ibm	Power9 System Firmware	>= fw930.00, < fw930.30
Ibm	Power9 System Firmware	>= fw940.00, < fw940.20
Ibm	Power9 System Firmware	< fw950.00
Ibm	Scale-Out Lc System Firmware	< op940.20

References

https://exchange.xforce.ibmcloud.com/vulnerabilities/197730VDB Entry, Vendor Advisory
https://www.ibm.com/support/pages/node/6455911Vendor Advisory
https://exchange.xforce.ibmcloud.com/vulnerabilities/197730VDB Entry, Vendor Advisory
https://www.ibm.com/support/pages/node/6455911Vendor Advisory

Timeline

Published: May 26, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20487?

IBM Power9 Self Boot Engine(SBE) could allow a privileged user to inject malicious code and compromise the integrity of the host firmware bypassing the host firmware signature verification process.

How severe is CVE-2021-20487?

CVE-2021-20487 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.68% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20487?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20487?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST