CVE-2026-16996

Analyzed Analyzed - Analysis Complete

Integer Underflow in IBM AIX and PowerVM VIOS

Publication date: 2026-08-20

Last updated on: 2026-08-25

Assigner: IBM Corporation

Description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to execute arbitrary code due to an integer underflow.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-20

Last Modified

2026-08-25

Generated

2026-09-10

AI Q&A

2026-08-21

EPSS Evaluated

2026-09-09

NVD

CVE-2026-16996

EUVD

EUVD-2026-63632

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-787	The product writes data past the end, or before the beginning, of the intended buffer.
CWE-191	The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

Attack-Flow Graph

Executive Summary

This vulnerability is an integer underflow issue in IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1. An attacker with local access could exploit this to execute arbitrary code on the system.

Detection Guidance

Detection of this vulnerability requires checking for IBM AIX 7.2, 7.3, or IBM PowerVM VIOS 4.1 systems. Review system logs for unusual activity or privilege escalation attempts. IBM may provide official patches or detection tools; check their support site for updates.

Impact Analysis

If exploited, this vulnerability could allow an attacker to gain control of the affected system, leading to unauthorized access, data theft, or further compromise of the environment.

Compliance Impact

This vulnerability allows local attackers to execute arbitrary code with high privileges due to an integer underflow. Such unauthorized code execution could lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR (data protection) and HIPAA (health information security).

Mitigation Strategies

Apply the latest IBM AIX or PowerVM VIOS security patches immediately. Monitor IBM's official advisories for updates. Restrict local user access to reduce attack surface until patches are applied.

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