Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a remote attacker to execute arbitrary code due to an integer overflow during size computation.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-20T22:17:14.360Z",
  "pubdate": "2026-08-20T22:17:14.360Z",
  "executiveSummary": "This security assessment analyzes a critical integer overflow vulnerability affecting IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. The flaw resides within the size computation logic of the affected operating systems and virtualization components. A remote attacker can leverage this vulnerability to execute arbitrary code within the context of the underlying system.\nThe primary impact of successful exploitation includes complete system compromise, unauthorized execution of arbitrary code, potential denial of service, and loss of confidentiality, integrity, and availability. The risk implications are severe, as enterprise environments utilizing these operating systems and virtualization appliances rely heavily on their isolation and stability.\nAttacker capabilities involve remote exploitation vectors where malicious input triggers the integer overflow condition during memory allocation or buffer size calculations. The vulnerability stems from improper handling of integer boundaries, leading to heap or stack corruption scenarios that facilitate arbitrary code execution without requiring prior authentication or privileged access, depending on the specific network-exposed service handling the malformed input.",
  "technicalDetails": "The root cause of the vulnerability is an integer overflow condition occurring during size computation routines within IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. When the affected system processes specially crafted input data, the arithmetic operations responsible for calculating required memory buffer sizes wrap around due to integer boundary limitations. This discrepancy results in the allocation of a memory buffer significantly smaller than what is required to store the incoming data.\nThe exploitation method leverages this calculated size mismatch to induce a buffer overflow condition, typically leading to heap or stack corruption. An attacker crafts a malicious payload containing oversized data designed to exceed the bounds of the undersized allocated buffer. As the system writes the input data into memory, adjacent memory structures, function pointers, or control flow data are overwritten with attacker-controlled values.\nThe attack flow proceeds as follows: First, the attacker identifies a vulnerable network service or local component within IBM AIX or IBM PowerVM VIOS that performs vulnerable size computations. Second, the attacker transmits a maliciously formatted request or input stream containing values engineered to trigger the integer overflow during parsing or allocation phases. Third, the size calculation wraps around, resulting in a dangerously small memory allocation. Fourth, the subsequent copy or write operation overflows the destination buffer, corrupting adjacent memory space. Finally, the attacker redirects execution flow to injected shellcode or executes arbitrary code payloads with the privileges of the compromised process.\nThe vulnerable components include core operating system modules and virtualization subsystems responsible for parsing data streams or managing memory allocation routines in IBM AIX versions 7.2 and 7.3, as well as IBM PowerVM VIOS version 4.1. Network exposure depends on the specific daemon or service exposed to the network perimeter that utilizes the flawed size computation logic. Authentication and privilege requirements are minimal for remote exploitation scenarios, allowing unauthenticated attackers to initiate the attack flow."
}