CVE-2026-4936 Power System Insufficient Entropy

Medium 5.1 Published 19 Aug 2026 Updated 20 Aug 2026

An attacker with service processor access can derive weak AES keys to decrypt protected data in IBM PowerVM Hypervisor.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-4936?

CVE-2026-4936 is a medium-severity vulnerability in IBM PowerVM Hypervisor, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-331

Which versions are affected by CVE-2026-4936?

It affects 26 products.

Products include Ibm Power System E1050 \(9043-Mrx\) Firmware, Ibm Power System E1080 \(9080-Hex\) Firmware, Ibm Power System E1150 \(9043-Mru\) Firmware, Ibm Power System E1180 \(9080-Heu\) Firmware, Ibm Power System E950 \(9040-Mr9\) Firmware, Ibm Power System E980 \(9080-M9s\) Firmware and 20 more.

How do I fix CVE-2026-4936?

No fix has been published for CVE-2026-4936 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-4936 being exploited?

There is no known exploitation of CVE-2026-4936 in the wild and no public exploit code.

Sources

Also known as GHSA-wmfq-mfcf-jvxp.