Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to cause a denial of service due to an out-of-bounds write.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.4",
  "pubDate": "2026-08-19T20:17:10.360Z",
  "pubdate": "2026-08-19T20:17:10.360Z",
  "executiveSummary": "This vulnerability represents a significant security flaw characterized by an out-of-bounds write condition affecting specific operating systems and virtualization management environments. The core vulnerability type is an out-of-bounds memory write, which can be maliciously triggered to induce a system-wide denial of service condition. The affected products include IBM AIX versions 7.2 and 7.3, as well as IBM PowerVM VIOS version 4.1.\nThe risk implications are severe for system availability, as successful exploitation results in system instability, kernel panics, or abrupt crashes, rendering critical enterprise workloads and virtualized infrastructures inaccessible. Regarding attacker capabilities and requirements, the vulnerability requires a local attacker to possess pre-existing access to the target system. Exploitation mechanics leverage localized privileges to interact with vulnerable internal kernel interfaces, device drivers, or system calls that fail to perform adequate boundary checking on input data prior to committing write operations to memory. Consequently, the absence of proper bounds validation permits the modification of adjacent memory structures, culminating in memory corruption and immediate service disruption.\nOrganizations utilizing the specified versions of IBM AIX and IBM PowerVM VIOS face availability risks from malicious actors or compromised low-privileged local accounts capable of executing arbitrary code or specialized binaries on the underlying host or virtual I/O server.",
  "technicalDetails": "The vulnerability stems from insufficient bounds checking within internal kernel components, device drivers, or memory management routines of IBM AIX 7.2, IBM AIX 7.3, and IBM PowerVM VIOS 4.1. Specifically, an out-of-bounds write flaw exists where input data or calculated memory offsets exceed allocated buffer boundaries during specific write operations.\nRoot cause analysis indicates that the affected code paths fail to adequately validate the size and length of input parameters supplied via local system interfaces before executing memory copy or direct assignment operations. When a local attacker passes maliciously crafted arguments or interacts with vulnerable kernel interfaces, the underlying logic writes data past the designated buffer limits, corrupting adjacent heap or stack memory structures, control data, or critical kernel state variables.\nThe attack flow proceeds as follows: First, the local attacker authenticates to the target IBM AIX or IBM PowerVM VIOS system with standard local user privileges. Second, the attacker formulates a payload or interacts with a specific local attack surface, such as a vulnerable device driver, system utility, or programmatic interface, designed to trigger the out-of-bounds condition. Third, the targeted component processes the untrusted input without performing rigorous boundary validation. Fourth, the write operation executes beyond the allocated memory boundaries, overwriting adjacent memory regions.\nThe exploitation requirements dictate that the threat actor must already have local execution capabilities on the host operating system or the Virtual I/O Server partition. Network exposure is indirect or non-existent for the initial vector, as the vulnerability is inherently local. Authentication is required in the form of a valid local user account. Privilege requirements depend on the specific vulnerable interface, but typically standard local user access or specific execution rights granted within the AIX or VIOS environment are sufficient to interact with the vulnerable component.\nThe payload behavior and post-exploitation impact manifest as memory corruption, which rapidly invalidates system integrity constraints. Because the out-of-bounds write targets internal kernel or system daemon memory spaces, the immediate consequence is an unhandled exception, kernel panic, or forced system crash. This directly achieves the denial of service objective by terminating critical operating system functions and disrupting all hosted logical partitions (LPARs) managed by the affected PowerVM VIOS instance."
}