CVE-2026-16835 in Power Systems Firmware
Summary
by MITRE • 08/19/2026
IBM Power Systems Firmware 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 FSP management network protocol. An unauthenticated attacker on the management network can bypass authentication and perform any administrative operation on the managed system, including control of partition power state, configuration, and console access across all hosted partitions, resulting in a confidentiality, integrity, and availability impact to the managed system.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified within IBM Power Systems firmware versions FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, and FW950.00 through FW950.H2 represents a critical failure in the authentication mechanisms of the Flexible Service Processor management network protocol. The FSP serves as the out-of-band management interface for IBM Power Systems servers, providing administrators with remote access to hardware-level controls such as power state management, system configuration, and console access independent of the operating system status. This specific flaw allows an unauthenticated attacker who has network connectivity to the management subnet to bypass these authentication requirements entirely. By exploiting this weakness in the protocol implementation, the adversary gains unrestricted administrative privileges on the managed system without presenting valid credentials or completing any form of identity verification process.
From a technical perspective, this vulnerability is classified under CWE-287, which denotes Improper Authentication. The root cause lies in the handling of management network requests where the firmware fails to enforce mandatory access control checks before processing administrative commands. This lack of validation permits malicious actors to inject crafted packets that mimic legitimate administrative traffic but omit or manipulate authentication tokens. Consequently, the system accepts these unauthorized requests as valid operations from a trusted administrator. This flaw fundamentally undermines the security boundary established by the management network architecture, which is typically designed to be isolated and secured against external threats through strict access controls and encryption protocols.
The operational impact of this vulnerability is severe due to the high level of control granted over the physical infrastructure. An attacker can exercise full administrative authority, including the ability to change partition power states, modify system configurations, and gain console access across all hosted partitions. This capability leads to a complete compromise of confidentiality, integrity, and availability for the managed systems. Confidentiality is compromised as sensitive data stored on or processed by the server becomes accessible to unauthorized parties. Integrity is affected because an attacker can alter critical configuration settings or install malicious firmware updates that persist through reboots. Availability is impacted through the potential to power off partitions or crash system services, leading to significant downtime and disruption of business operations hosted on these systems.
In terms of threat modeling, this vulnerability aligns with MITRE ATT&CK techniques related to Initial Access via Network Service Exposure and Privilege Escalation by exploiting authentication bypasses. Attackers can leverage this flaw during the initial intrusion phase if they have reached the management network segment, often through lateral movement from compromised workstations or misconfigured network segmentation policies. The ability to control partition power states also facilitates persistence mechanisms where an attacker might ensure their access is maintained even after system restarts by modifying boot configurations or disabling security features remotely.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. IBM has released firmware updates that address this authentication bypass flaw, making the application of these patches the primary defense mechanism. Organizations should prioritize updating all affected Power Systems to the latest recommended firmware versions as soon as possible. In addition to patching, network segmentation is critical; the management network containing FSP interfaces must be isolated from general corporate or public networks using firewalls and VLANs that restrict access only to authorized administrative workstations. Implementing strict firewall rules that limit source IP addresses allowed to communicate with the FSP can significantly reduce the attack surface. Furthermore, enabling multi-factor authentication where supported by newer firmware versions adds an additional layer of security beyond simple password-based or token-based credentials. Regular audits of network traffic on management interfaces and monitoring for anomalous administrative activity can also aid in early detection of exploitation attempts.