Is CVE-2021-20487 in the CISA KEV catalog?

No. CVE-2021-20487 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-20487?

CVE-2021-20487 has a CVSS v3 base score of 9.1 (CRITICAL).

What is the EPSS score for CVE-2021-20487?

CVE-2021-20487 has an EPSS score of 0.68% (48th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-20487?

Upgrade power9 system firmware to fw950.00 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-20487

CRITICAL

9.1

CVSS v3

NVD

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.

CWE-347

How to fix

Remediation Available

power9 system firmwareNVD

Affected:< fw950.00Fixed in:fw950.00CVE-2021-20487derived from NVD

scale-out lc system firmwareNVD

Affected:< op940.20Fixed in:op940.20CVE-2021-20487derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.68%probability of exploitation in 30 days

48thpercentile

Moderate risk: more likely to be exploited than 48% of all known CVEs.

References

Vendor Advisory2

Related Vulnerabilities

Other CWE-347 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2018-16042	Medium	6.5	82%	-	-
CVE-2025-59718	Critical	9.8	66%	KEV	Fix
CVE-2025-25292	Critical	9.8	64%	-	Fix
CVE-2021-22160	Critical	9.8	53%	-	Fix
CVE-2013-3900	Medium	5.5	45%	KEV	-
CVE-2018-0114	High	7.5	43%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.