CVE-2026-4936: Power System Insufficient Entropy

Severity: medium (CVSS 6.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-19 · updated 2026-08-25
Weakness: CWE-331

Description

IBM PowerVM Hypervisor Platform KeyStore (PKS) and virtual TPM FW1110.00 through FW1110.20, FW1060.00 through FW1060.71, and FW950.00 through FW950.H2 use persistent storage key seeds that result in an AES key with reduced strength. An attacker with access to the service processor or HMC could exploit this weakness to derive the encryption key and access the data.

Affected products

IBM Power System E1050 (9043-Mrx) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System E1080 (9080-Hex) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System E1150 (9043-Mru) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System E1180 (9080-Heu) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System E950 (9040-Mr9) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System E980 (9080-M9S) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System H922 (9223-22S) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System H924 (9223-42S) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System L1022 (9786-22H) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System L1024 (9786-42H) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System L1122 (9856-22H) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System L1124 (9856-42H) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System S1012 (9028-21B) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System S1014 (9105-41B) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System S1022 (9105-22A) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System S1022S (9105-22B) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System S1024 (9105-42A) Firmware: from fw1060.00 before fw1060.72 — fixed in fw1060.72
IBM Power System S1112 (9242-21B) Firmware: fw1120.00
IBM Power System S1112 (9242-21T) Firmware: fw1120.00
IBM Power System S1114 (9824-41B) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System S1122 (9824-22A) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System S1122S (9824-22B) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System S1124 (9824-42A) Firmware: from fw1110.00 before fw1110.30; fw1120.00 — fixed in fw1110.30
IBM Power System S914 (9009-41G) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System S922 (9009-22G) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3
IBM Power System S924 (9009-42G) Firmware: from fw950.00 before fw950.h3 — fixed in fw950.h3

How to fix

Upgrade to a fixed version: IBM Power System E1050 (9043-Mrx) Firmware fw1060.72; IBM Power System E1080 (9080-Hex) Firmware fw1060.72; IBM Power System E1150 (9043-Mru) Firmware fw1110.30; IBM Power System E1180 (9080-Heu) Firmware fw1110.30; IBM Power System E950 (9040-Mr9) Firmware fw950.h3; IBM Power System E980 (9080-M9S) Firmware fw950.h3; IBM Power System H922 (9223-22S) Firmware fw950.h3; IBM Power System H924 (9223-42S) Firmware fw950.h3; IBM Power System L1022 (9786-22H) Firmware fw1060.72; IBM Power System L1024 (9786-42H) Firmware fw1060.72; IBM Power System L1122 (9856-22H) Firmware fw1110.30; IBM Power System L1124 (9856-42H) Firmware fw1110.30. Check the vendor advisory for mitigations.

References

https://www.ibm.com/support/pages/node/7283890

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