ReviewHigh

CVE-2026-16661

IBM PowerVM Hypervisor

IBM PowerVM Hypervisor FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, and FW950.00 through FW950.H2 is affected by a vulnerability in the service processor mailbox interface. An attacker with authenticated service-level access to the FSP can exploit this vulnerability, allowing arbitrary code to be executed in the host firmware runtime, giving full control over the managed system, resulting in a confidentiality, integrity, and availability impact to the managed system.

CVSS: 8.2
EPSS: 0.13%
CISA KEV: Not listed
Published: 2026.08.20

PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.13%

Technical severityCVSS 8.2

Vulnerability overview

Affected product and versions

Product: IBM PowerVM Hypervisor
Affected versions: >= FW1120.00, >= FW1110.00 <= FW1110.30, >= FW1060.00 <= FW1060.80, >= FW950.00 <= FW950.H2
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that IBM PowerVM Hypervisor and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CWE: CWE-190