Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a remote attacker to cause a denial of service due to improper validation of an allocation size.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-08-20T22:17:15.067Z",
  "pubdate": "2026-08-20T22:17:15.067Z",
  "executiveSummary": "This vulnerability involves an improper validation of an allocation size flaw affecting IBM AIX and IBM PowerVM VIOS. The vulnerability allows a remote attacker to induce a denial of service condition on targeted systems. Specifically, the affected software versions include IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. The risk implication is significant as it threatens system availability, potentially disrupting critical operations managed by the hypervisor and operating system environments. The exploitation of this vulnerability enables an unauthorized remote threat actor to exhaust system resources or trigger anomalous memory allocation behavior without requiring complex interaction or prior privileges, depending on the network exposure and protocol implementation details. Mitigation requires applying vendor-supplied fixes or adhering to recommended security advisories to ensure proper bounds checking and validation logic is enforced during memory allocation routines.",
  "technicalDetails": "The root cause of the vulnerability stems from improper validation of an allocation size parameter within the affected memory management or request parsing routines of IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. When the system processes incoming requests or internal data structures, it fails to adequately verify whether the specified allocation size falls within acceptable, safe boundaries before committing system resources.\nExploitation occurs when a remote attacker crafts and transmits a malicious payload or input sequence designed to manipulate the unvalidated allocation size parameter. Upon receipt, the vulnerable component processes the malformed size metric, leading to excessive memory consumption, integer overflow conditions, or memory corruption scenarios that destabilize the operating system kernel or the PowerVM VIOS environment.\nThe attack flow proceeds as follows: First, the attacker identifies a network-exposed service or interface handling allocation requests on the target IBM AIX or VIOS system. Second, the attacker transmits a specially formatted request containing an invalid or maliciously oversized allocation parameter. Third, the parsing engine or memory allocation subsystem fails to perform rigorous input validation, accepting the anomalous size value. Fourth, the system attempts to allocate resources based on this unverified metric, resulting in a system crash, severe performance degradation, or an unhandled exception that culminates in a denial of service.\nThe vulnerable components reside within the core architecture of IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. The flaw requires network exposure to the vulnerable service, though specific authentication and privilege requirements depend on the exact vector exposed by the affected interface. The post-exploitation impact is strictly confined to availability degradation, causing immediate operational disruption of the affected logical partitions or the underlying VIOS management plane."
}