CVE-2026-16991

Analyzed Analyzed - Analysis Complete

Privilege Escalation in IBM AIX and PowerVM VIOS via Symbolic Link Handling

Publication date: 2026-08-20

Last updated on: 2026-08-27

Assigner: IBM Corporation

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-20

Last Modified

2026-08-27

Generated

2026-09-10

AI Q&A

2026-08-21

EPSS Evaluated

2026-09-09

NVD

CVE-2026-16991

EUVD

EUVD-2026-63631

Affected Vendors & Products

Vendor	Product	Version / Range
ibm	vios	From 4.1.0 (inc) to 4.1.0.50 (exc)
ibm	vios	From 4.1.1.0 (inc) to 4.1.1.30 (exc)
ibm	vios	From 4.1.2.0 (inc) to 4.1.2.20 (exc)
ibm	aix	From 7.2.5 (inc) to 7.2.5.212 (inc)
ibm	aix	From 7.3.2 (inc) to 7.3.2.5 (inc)
ibm	aix	From 7.3.3 (inc) to 7.3.3.2 (inc)
ibm	aix	From 7.3.4 (inc) to 7.3.4.1 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-269	The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Attack-Flow Graph

Executive Summary

This vulnerability in IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1 allows a local attacker to gain elevated privileges by exploiting improper handling of symbolic links. This could let the attacker perform unauthorized actions on the system.

Detection Guidance

This vulnerability involves improper handling of symbolic links in IBM AIX and PowerVM VIOS. Detection requires checking for vulnerable versions of these systems and reviewing file permissions. No specific commands are provided in the context, but you should verify system versions against IBM advisories and audit symbolic link handling in critical directories.

Impact Analysis

If exploited, this vulnerability could allow an attacker with local access to gain higher privileges, potentially leading to full system compromise. This may result in unauthorized data access, system manipulation, or disruption of services.

Compliance Impact

This vulnerability allows local attackers to gain elevated privileges through improper handling of symbolic links. Such privilege escalation could lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR (data protection) and HIPAA (health information security) by exposing personal or protected health information.

Mitigation Strategies

Apply IBM-provided patches or updates for AIX 7.2, 7.3, and PowerVM VIOS 4.1 to address improper symbolic link handling. Monitor IBM security advisories for fixes and restrict local user access until patches are applied.

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