CVE-2026-16933 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, FW950.00 through FW950.H2, OP940.00 through OP940.a1 (Power9), and OP940.00 through OP940.81 (Power HMC) is affected by a vulnerability in the interface between the BMC/FSP and the host system. An attacker with service account or root access to the BMC/FSP can read and write arbitrary regions of host system memory, giving full control over the host system and all hosted partitions, resulting in a confidentiality, integrity, and availability impact.
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Analysis
by VulDB Data Team • 08/19/2026
The vulnerability identified within IBM Power Systems firmware versions FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, FW950.00 through FW950.H2, OP940.00 through OP940.a1 for Power9 processors, and OP940.00 through OP940.81 for the Power HMC represents a critical failure in the security boundary between the Baseboard Management Controller or Flexible Service Processor and the host system processor. This architecture relies on a trusted interface to facilitate hardware-level management tasks such as remote console access, power control, and firmware updates. However, the implementation of this communication channel lacks sufficient validation mechanisms for memory address ranges requested by the BMC/FSP during read or write operations against the host's physical memory space. Consequently, an attacker who has already compromised the service account credentials or obtained root-level administrative privileges on the BMC/FSP can exploit this flaw to bypass standard operating system protections and directly manipulate arbitrary regions of the host system memory.
From a technical perspective, this issue is classified under CWE-787: Out-of-bounds Write and CWE-125: Out-of-bounds Read, as it allows access beyond intended boundaries due to improper validation of input parameters related to memory addresses. The absence of strict bounds checking enables the attacker to perform arbitrary read and write operations on host memory, effectively neutralizing any isolation mechanisms provided by hypervisors or partitioning software. This capability aligns with ATT&CK technique T1057: Process Discovery when used for reconnaissance, but more critically it maps to T1068: Exploitation for Privilege Escalation and potentially T1499: Endpoint Denial of Service if the memory corruption leads to system instability. The core flaw lies in the trust assumption that any request originating from a privileged BMC/FSP account is inherently safe, ignoring the potential for credential theft or insider threats within the management plane.
The operational impact of this vulnerability is severe and comprehensive, affecting confidentiality, integrity, and availability simultaneously. Because an attacker can read arbitrary memory regions, they can extract sensitive data such as encryption keys, session tokens, user credentials, and proprietary application logic stored in RAM, leading to a complete breach of confidentiality. The ability to write to arbitrary memory locations allows for the modification of critical system structures, kernel code, or partition configurations, which compromises integrity by enabling persistent backdoors, privilege escalation on the host OS, or manipulation of virtual machine states across partitions. Furthermore, malicious writes can corrupt essential data structures leading to immediate system crashes, blue screens, or firmware corruption, resulting in a total denial of service for all hosted workloads and disrupting business continuity.
Mitigation strategies must focus on both technical remediation and administrative controls. The primary defense is the immediate application of vendor-provided firmware updates that patch this specific interface vulnerability, ensuring that memory access requests are strictly validated against allowed ranges before execution. In environments where updating firmware is not immediately feasible, organizations should enforce strict network segmentation to isolate BMC/FSP management interfaces from untrusted networks and restrict physical access to server rooms. Additionally, implementing multi-factor authentication for service accounts with elevated privileges on the BMC/FSP reduces the risk of credential compromise that could lead to exploitation. Regular auditing of administrative actions within the management console and monitoring for anomalous memory access patterns can also help in detecting potential attempts to exploit this flaw before significant damage occurs.