CVE-2026-16890 in AIX
Summary
by MITRE • 08/19/2026
IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to obtain sensitive information or cause a denial of service due to an integer overflow.
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Analysis
by VulDB Data Team • 08/19/2026
The vulnerability identified in IBM AIX versions 7.2 and 7.3, as well as IBM PowerVM Virtual I/O Server (VIOS) version 4.1, represents a critical class of software defects known as integer overflows. This specific flaw allows a local attacker to exploit improper handling of numerical values within the operating system's core components or virtualization management layers. When an application or system process performs arithmetic operations on user-controlled input without adequate validation bounds checking, it may result in an integer overflow condition. In such scenarios, the calculated value exceeds the maximum limit that can be represented by the allocated data type, causing it to wrap around to a significantly smaller number or negative value. This miscalculation often leads to incorrect memory allocation sizes during subsequent operations, which is a precursor to more severe exploitation vectors including buffer overflows and arbitrary code execution, although in this specific instance, the immediate consequences are limited to information disclosure and denial of service.
From an operational perspective, the impact of this vulnerability is twofold, affecting both confidentiality and availability within the affected IBM environments. For local attackers who have already gained a foothold on the system through other means or via compromised user accounts, the integer overflow can be leveraged to read sensitive memory contents that were not intended for public access. This could include cryptographic keys, session tokens, or proprietary data structures residing in kernel space or privileged application memory. Furthermore, the vulnerability enables denial of service attacks by causing critical system processes to crash or hang due to invalid memory accesses triggered by the overflowed values. In a virtualized environment like PowerVM VIOS, such instability can disrupt multiple guest logical partitions, leading to widespread outages and impacting business continuity for organizations relying on these systems for their infrastructure needs.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-190, which defines integer overflow or wraparound errors. It also relates closely to CWE-682 regarding incorrect calculation of buffer size, as the primary risk stems from allocating insufficient memory based on miscalculated lengths. In terms of adversary tactics and techniques, this flaw supports ATT&CK technique T1530, Data from Local System, by facilitating unauthorized data exfiltration, and T1499, Endpoint Denial of Service, through system instability. The local nature of the exploit means that an attacker must first bypass authentication controls or leverage existing privileges to interact with the vulnerable components, highlighting the importance of strict access control policies even within trusted internal networks.
Mitigation strategies for this vulnerability primarily involve applying the official patches and service updates provided by IBM for AIX 7.2, 7.3, and PowerVM VIOS 4.1. Organizations should prioritize updating these systems to ensure that the underlying code handles integer arithmetic with proper bounds checking and validation mechanisms in place. Additionally, implementing defense-in-depth measures such as strict user privilege separation can limit the potential impact of a local attacker attempting to exploit this flaw. Security teams should also monitor system logs for unusual patterns indicative of memory access violations or process crashes, which may signal an attempted exploitation of this integer overflow vulnerability before it leads to significant data loss or service disruption.