Description

IBM PowerVM Hypervisor FW1120.00, FW1110.00 through FW1110.30, and FW1060.00 through FW1060.80 could allow a local attacker to obtain sensitive information or cause a denial of service due to improper control of format strings.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.2",
  "pubDate": "2026-08-19T15:16:56.413Z",
  "pubdate": "2026-08-19T15:16:56.413Z",
  "executiveSummary": "A format string vulnerability has been identified in the IBM PowerVM Hypervisor, specifically affecting firmware versions FW1120.00, FW1110.00 through FW1110.30, and FW1060.00 through FW1060.80. This security defect arises from the improper control of format string specifiers within the hypervisor codebase, allowing an unauthorized or locally authenticated entity to interact with vulnerable functions insecurely.\nThe primary impact of this vulnerability encompasses the potential disclosure of sensitive system information and the induction of a denial of service condition against the hypervisor. In a virtualization environment, compromising the hypervisor poses severe risk implications, as it undermines the security isolation boundaries protecting guest partitions and shared hardware resources.\nExploitation of this flaw requires local access to the target system and appropriate execution capabilities within the hypervisor context. An attacker leveraging this vulnerability can craft malicious input containing format string specifiers, which are subsequently parsed unsanitized by logging or output generation functions. This compromises the confidentiality and availability of the affected IBM PowerVM Hypervisor deployments.",
  "technicalDetails": "The root cause of this vulnerability is improper control of format strings within the IBM PowerVM Hypervisor internal handling routines. Specifically, input data containing format specifiers such as percent symbols is passed directly to standard input/output formatting functions without adequate sanitization or strict format string enforcement, violating secure coding practices.\nThe vulnerable component resides within the core subsystems of the IBM PowerVM Hypervisor affecting firmware releases FW1120.00, FW1110.00 through FW1110.30, and FW1060.00 through FW1060.80. The issue manifests when the hypervisor processes maliciously crafted strings through vulnerable logging, debugging, or error-reporting functions that evaluate user-supplied data as format arguments.\nThe attack flow proceeds in a step-by-step manner where a local attacker initiates execution within a context capable of interacting with the hypervisor management or logging interfaces. The attacker supplies a specifically crafted payload containing format specifiers such as %p, %x, or %n. When the hypervisor processes this input and passes it as the format argument to a function like printf or a proprietary internal equivalent, the underlying formatting engine evaluates the supplied format specifiers against the call stack and memory structures.\nDuring exploitation, the improper parsing of format specifiers allows the attacker to read arbitrary memory contents by traversing the stack pointers, resulting in the unauthorized disclosure of sensitive information such as memory addresses, encryption keys, or internal operational data. Furthermore, utilizing write-back specifiers like %n or inducing malformed memory reads and writes can trigger memory corruption, leading to application crashes, instability, and a subsequent denial of service condition for the hypervisor environment.\nAuthentication and privilege requirements involve local system access with permissions sufficient to trigger the vulnerable code paths within the hypervisor. Network exposure is typically restricted unless management interfaces bridging network layers directly feed unvalidated inputs into the affected formatting routines. Post-exploitation impact centers on host-level compromise, information leakage across logical partitions, and complete disruption of virtualized workloads hosted on the affected IBM Power hardware."
}