CVE-2026-16938 in Power Systems
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 access controls over privileged system configuration operations on the FSP. An attacker with authenticated administrator-level access to the FSP can place the managed system into a non-production operational mode, allowing certain system components to be disabled. This condition persists across FSP resets and requires explicit operator intervention — clearing the affected configuration — to restore normal operation. Successful exploitation results in an availability impact to the managed system.
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Analysis
by VulDB Data Team • 08/21/2026
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 significant flaw in the access control mechanisms governing privileged system configuration operations on the Flexible Service Processor. The Firmware Security Processor acts as a critical management interface for IBM Power Systems, providing out-of-band management capabilities that are essential for monitoring, diagnosing, and controlling the physical hardware state of the server infrastructure. In this specific instance, the security architecture fails to adequately restrict or validate certain administrative commands related to system operational modes. This deficiency allows an attacker who has already obtained authenticated administrator-level access credentials to manipulate the firmware configuration in a manner that bypasses intended safety checks for production environments. The core technical flaw lies not in the authentication mechanism itself, but rather in the authorization logic and state management of the FSP when processing commands that alter the system's operational profile.
When an attacker exploits this vulnerability, they can force the managed system into a non-production operational mode. This specific configuration change is designed to disable certain critical system components, effectively reducing the server's functionality or rendering it unable to serve its intended purpose in a production environment. The impact of this action is primarily categorized as a denial of service against the availability of the affected hardware resources. Because the vulnerability involves changing deep-level firmware settings that dictate how the hardware behaves at a fundamental level, the resulting state change persists even if the system undergoes a reset or reboot cycle. This persistence indicates that the malicious configuration is being written to non-volatile storage within the FSP rather than existing only as temporary runtime memory states. Consequently, simply restarting the server does not remediate the issue; the compromised operational mode remains active until an operator explicitly intervenes to clear the affected configuration and restore normal operation parameters.
From a threat modeling perspective, this vulnerability aligns with CWE-269, which describes Improper Privilege Control, specifically where administrative privileges are used in ways that violate security policy or intended system behavior. Furthermore, it maps directly to MITRE ATT&CK technique T1531, Access Denial via Resource Destruction, as the attacker is leveraging their elevated access to degrade service availability by disabling essential components. The requirement for authenticated administrator-level access suggests that this vulnerability would typically be exploited in scenarios where an insider threat actor has compromised or been granted high-privilege credentials, or if there are secondary vulnerabilities allowing privilege escalation from a lower-privileged account to the FSP admin level. It is less likely to be exploitable by external attackers without prior network compromise and credential theft due to the authentication barrier.
Mitigation strategies for this vulnerability must focus on both immediate remediation and long-term hardening of the management infrastructure. The primary mitigation involves applying the firmware updates provided by IBM that address these specific access control flaws in the affected versions listed above. Organizations should prioritize patching systems running FW1060, FW950, FW1110, or FW1120 series firmwares to ensure the underlying code correctly validates and restricts configuration changes related to operational modes. In addition to firmware updates, security teams should enforce strict access control policies for the Flexible Service Processor interface. This includes restricting network access to the FSP management ports using firewalls and VLAN segmentation, ensuring that only authorized administrative workstations can communicate with the hardware management interfaces. Furthermore, implementing multi-factor authentication for administrator accounts accessing the FSP adds a critical layer of defense against credential theft or brute-force attacks that could lead to exploitation of this configuration flaw. Regular auditing of administrative actions logged by the FSP is also recommended to detect any unauthorized attempts to change system operational modes before they result in service disruption.