CVE-2026-96262 in PowerVM Hypervisor
Summary
by MITRE • 10/13/2026
IBM Power Systems Firmware FW1060.00 through FW1060.81 is affected by a vulnerability in the service processor mailbox interface. An attacker with authenticated service-level access to the FSP can send a specially crafted mailbox message to overflow host firmware runtime attribute storage, allowing arbitrary code to be executed in the host firmware runtime. This gives the attacker full access to the managed system's memory and hardware interfaces, resulting in a confidentiality, integrity, and availability impact to the managed system.
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Analysis
by VulDB Data Team • 10/13/2026
The vulnerability identified within IBM Power Systems Firmware versions FW1060.00 through FW1060.81 represents a critical security flaw located in the service processor mailbox interface. This component serves as a communication bridge between the Flexible Service Processor, which manages hardware-level operations and out-of-band management, and the host firmware that controls the operating system environment. The core technical issue stems from an improper validation of input data within this interface mechanism. Specifically, when an attacker possesses authenticated service-level access to the FSP, they are able to transmit a specially crafted mailbox message designed to exploit weaknesses in how the host firmware processes incoming requests. This malformed or oversized payload triggers a buffer overflow condition that corrupts the host firmware runtime attribute storage area.
From a technical perspective, this flaw is classified under CWE-120, which denotes Buffer Copy without Checking Size of Input, and more specifically relates to stack-based or heap-based overflows depending on the internal implementation details of the attribute storage structure. The exploitation of this vulnerability allows an attacker to overwrite critical memory locations within the host firmware runtime environment. By carefully crafting the overflow payload, it is possible to manipulate control flow data such as return addresses or function pointers. This manipulation enables the execution of arbitrary code with the privileges granted to the host firmware process. Such a scenario effectively bypasses standard security boundaries because the service processor typically operates at a higher privilege level than the guest operating systems running on the hardware, yet this specific interface flaw allows lateral movement into the host runtime space where further exploitation can occur.
The operational impact of successfully exploiting this vulnerability is severe and comprehensive. Once arbitrary code execution is achieved within the host firmware runtime, the attacker gains full access to the managed system's physical memory and direct interfaces with underlying hardware components. This level of control facilitates a complete compromise of confidentiality, integrity, and availability. Confidentiality is compromised as the attacker can read sensitive data stored in memory or intercepted by the firmware. Integrity is undermined because the attacker can modify critical system files, boot processes, or security configurations without detection. Availability is impacted through the potential to crash the host firmware, leading to a denial of service for all virtual machines and operating systems hosted on that physical server. Furthermore, this access could be used to install persistent rootkits or hardware-level malware that survives OS reinstalls and reboots.
In terms of threat modeling, this vulnerability aligns with MITRE ATT&CK techniques related to privilege escalation and component firmware exploitation. An attacker leveraging this flaw would likely follow a path involving initial authentication via the service processor interface followed by exploitation of the buffer overflow to gain elevated privileges within the host environment. This represents a significant risk in enterprise data centers where IBM Power Systems are deployed for mission-critical workloads, as it undermines the trust model that relies on the isolation between management processors and guest operating systems.
To mitigate this vulnerability, organizations must immediately apply the firmware updates provided by IBM that address the input validation logic within the service processor mailbox interface. It is crucial to ensure that all affected systems running FW1060.00 through FW1060.81 are patched to a version where this buffer overflow has been remediated. In addition to patching, administrators should enforce strict access controls on the Flexible Service Processor interfaces. This includes restricting network connectivity to management ports, implementing strong authentication mechanisms such as multi-factor authentication for service-level accounts, and monitoring logs for unusual mailbox message patterns or failed login attempts that might indicate probing activity. Regular audits of firmware versions across the infrastructure are also recommended to ensure compliance with security baselines and timely application of vendor-supplied fixes.