CVE-2026-4932 in PowerVM Hypervisor
Summary
by MITRE • 07/28/2026
IBM PowerVM Hypervisor FW1110.00 through FW1110.20, and FW1060.00 through FW1060.71 could allow an attacker with physical access to the Transparent Memory Encryption (TME) hardware to decrypt encrypted memory due to insufficient cryptographic entropy.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability affects IBM PowerVM hypervisor versions ranging from FW1110.00 through FW1110.20 and FW1060.00 through FW1060.71, specifically impacting systems utilizing Transparent Memory Encryption hardware. The flaw stems from insufficient cryptographic entropy during the encryption key generation process, which creates predictable or weak cryptographic material that can be exploited by adversaries with physical access to the target system. When an attacker gains physical access to TME-enabled hardware, they can potentially decrypt memory contents that should remain protected through cryptographic means.
The technical implementation of this vulnerability resides in the cryptographic key derivation functions used by the PowerVM hypervisor when managing memory encryption operations. Weak entropy sources during key generation result in insufficient randomness that allows attackers to perform cryptanalytic attacks or brute force attempts against the encryption keys. This weakness directly violates fundamental cryptographic principles and represents a critical failure in the implementation of secure key generation mechanisms. The vulnerability operates at the hypervisor level where memory encryption controls are managed, making it particularly dangerous as it can affect all virtual machines running on the compromised system.
The operational impact of this vulnerability extends beyond simple data confidentiality breaches, as it allows attackers with physical access to potentially extract sensitive information from encrypted memory regions across multiple virtual environments. This creates a significant risk for organizations deploying PowerVM hypervisors in cloud computing or multi-tenant environments where isolation between virtual machines is expected. The attack surface is limited to physical access scenarios, but this still represents a critical weakness in the security model since physical security controls may be circumvented through various attack vectors including social engineering, insider threats, or compromised administrative access.
Organizations should immediately implement firmware updates from IBM addressing this vulnerability, ensuring proper entropy sources are configured for cryptographic operations. System administrators must also review and strengthen physical security measures around PowerVM systems, particularly those handling sensitive data. The remediation process should include comprehensive testing of updated firmware versions to ensure compatibility with existing virtual environments while maintaining the enhanced cryptographic protections. Additionally, organizations should consider implementing additional monitoring controls to detect potential exploitation attempts and establish incident response procedures specifically addressing this type of hardware-level cryptographic weakness.
This vulnerability aligns with CWE-330, which describes insufficient entropy in cryptographic systems, and corresponds to techniques documented in the MITRE ATT&CK framework under credential access and defense evasion categories. The weakness demonstrates how inadequate entropy generation can create exploitable conditions in hardware security modules and highlights the importance of proper random number generation in cryptographic implementations. Organizations should also consider implementing hardware security module validation procedures and regular cryptographic assessments to identify similar weaknesses in their infrastructure deployments.