Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to gain elevated privileges due to improper handling of symbolic links.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-20T22:17:10.317Z",
  "pubdate": "2026-08-20T22:17:10.317Z",
  "executiveSummary": "A local privilege escalation vulnerability exists within IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1. The vulnerability stems from improper handling of symbolic links by the affected operating systems and virtualization management components. This flaw allows a localized, authenticated threat actor with low privileges to manipulate symbolic link resolution pathways during specific system operations. Successful exploitation of this vulnerability results in unauthorized privilege escalation, potentially enabling the attacker to execute arbitrary commands or access restricted system resources with elevated administrative privileges. The risk implication is significant as it compromises the core security boundary of multi-tenant or shared enterprise environments running the affected AIX and VIOS versions. Exploitation requires local access to the target host and relies on standard user capabilities prior to triggering the vulnerable code path. No network exposure is required for the initial exploitation vector, making it primarily a threat vector for malicious insiders or compromised low-privileged service accounts.",
  "technicalDetails": "The root cause of the vulnerability resides in the insecure handling and resolution of symbolic links by privileged components within IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1. Specifically, when the operating system or virtualization layer interacts with files or directories in a context where trust boundaries are crossed, it fails to adequately validate the target of a symbolic link or prevent race conditions such as Time-of-Check to Time-of-Use (TOCTOU).\nAn authenticated local attacker leverages this improper handling by creating strategically placed symbolic links within writable file system locations that point to sensitive system files, configuration files, or execution binaries typically protected from standard users. When the vulnerable component executes privileged file operations—such as reading, writing, or traversing directories without safely verifying the destination—it follows the attacker-controlled symbolic link.\nThe attack flow proceeds as follows: First, the attacker identifies a vulnerable setuid binary, background daemon, or administrative script that interacts with file system objects insecurely. Second, the attacker establishes a symbolic link structure designed to intercept or redirect the privileged file operation. Third, the attacker initiates or waits for the privileged routine to execute. As the component processes the path, it traverses the symbolic link, inadvertently applying permissions or modifying data at the attacker's designated target location. Finally, through careful manipulation of file contents or metadata resulting from this unintended access, the attacker achieves arbitrary code execution or modifies critical system configurations to elevate their access level to root or equivalent administrative privileges.\nThe affected components are core OS utilities and virtualization management binaries within IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1. Exploitation requires local authentication on the target system, low local privilege levels, and does not involve network protocols or remote exposure."
}