CVE-2021-20487

mediumpriority · track · 36EPSS 0.007 · 52 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.68% (52nd) EPSS

CVSS 6.5 · medium

Is it mine?

8 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

9.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.5–9.1

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.3 · impact 6

v3.08highCVSS:3.0/AV:N/UI:N/I:H/AC:H/PR:H/S:C/A:H/C:H/E:U/RL:O/RC:Csecondary · ENISA EU

v3.08highCVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:Hsecondary · psirt@us.ibm.com USexploitability 1.3 · impact 6

v3.18.3highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-347USprimary

affected products (8)

Products and version ranges known to be affected.

IBM Power 9 Systems≤ FW930enisa_euvdEU
IBM Power 9 Systems≤ OP940enisa_euvdEU
IBM Power 9 Systems≤ FW940enisa_euvdEU
IBM Power 9 Systems≤ FW941enisa_euvdEU
ibm power9 system firmware< fw950.00nvdUScpe:2.3:o:ibm:power9_system_firmware:*:*:*:*:*:*:*:*
ibm power9 system firmwarefw930.00 → fw930.30nvdUScpe:2.3:o:ibm:power9_system_firmware:*:*:*:*:*:*:*:*
ibm power9 system firmwarefw940.00 → fw940.20nvdUScpe:2.3:o:ibm:power9_system_firmware:*:*:*:*:*:*:*:*
ibm scale-out lc system firmware< op940.20nvdUScpe:2.3:o:ibm:scale-out_lc_system_firmware:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-05-26modified 2026-06-17

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references (9)

External citations — patches, advisories, analysis.

scry

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