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.
Published: 2026-08-20
Score: 8.8 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

An integer underflow in IBM AIX versions 7.2 and 7.3 and IBM PowerVM VIOS 4.1 permits a local attacker running on a vulnerable system to execute arbitrary code. This flaw is an out‑of‑bounds write (CWE‑787) that can compromise confidentiality, integrity, and availability by corrupting data or gaining control of the affected system. Because the vulnerability is accessed locally, privilege escalation is possible but does not provide network‑wide reach beyond the local system.

Affected Systems

IBM AIX systems running 7.2 TL05 (SP13), 7.3 TL04 (SP2), 7.3 TL03 (SP3) and 7.3 TL02 (SP5) are affected. IBM PowerVM VIOS 4.1.0 with Fix Pack 4.1.0.50, 4.1.1 with Fix Pack 4.1.1.30 and 4.1.2 with Fix Pack 4.1.2.20 must be patched.

Risk and Exploitability

The CVSS score of 8.8 classifies the vulnerability as high severity. EPSS data indicates an exploitation probability of less than 1%, and the flaw is not listed in the CISA KEV catalog. However, local attack requirements mean that any user with local administrative or root access could exploit the integer underflow directly. IBM recommends applying the published Service Packs or Fix Packs immediately, performing a Live Update on AIX or a controlled reboot on VIOS to complete the update, and for VIOS 4.1.0/4.1.1 to migrate to Postgres15 following IBM’s post‑update guidance before resuming normal operation.

Generated by OpenCVE AI on August 25, 2026 at 17:38 UTC.

Remediation

Vendor Solution

A.  APARS IBM has assigned the following APARs to this problem: AIX LevelAPARAvailability  SPKEY7.2.5IJ5956608/14/2026SP13key_w_apar7.3.2IJ5956508/14/2026SP05key_w_apar7.3.3IJ5956408/14/2026SP03key_w_apar7.3.4IJ59563 08/14/2026SP02key_w_apar VIOS LevelAPARAvailability SPKEY4.1.0IJ5956508/14/20264.1.0.50key_w_apar4.1.1IJ5956408/14/20264.1.1.30key_w_apar4.1.2IJ5956308/14/20264.1.2.20key_w_apar B.  FIXES IBM strongly recommends addressing the vulnerability now.  AIX and VIOS fixes are available and can be downloaded from Fix Central: https://www.ibm.com/support/fixcentral  An LPAR reboot is required to complete the SP/FP update. On AIX, Live Update can be used to avoid a reboot.  IBM has assigned the following AIX Service Packs (SPs) and VIOS Fix Packs (FPs) as the remediation levels for the published vulnerabilities. AIX Level Service PackAIX 7.3 TL04SP2AIX 7.3 TL03SP3AIX 7.3 TL02SP5AIX 7.2 TL05 SP13 PowerVM VIOS LevelFix PackVIOS 4.1.2 4.1.2.20VIOS 4.1.1 4.1.1.30VIOS 4.1.0  4.1.0.50 Note: These SPs/FPs are cumulative and include fixes for all previously published AIX/VIOS security vulnerabilities. They can be applied on top of any earlier affected level of the TL . Note: To apply these patches using nimsh secure, special steps must be taken as the protocol between master and client is updated to be more secure. Please read this article: https://www.ibm.com/support/pages/node/7283157 Note: For VIOS 4.1.0 and VIOS 4.1.1, additional steps are required to migrate to the latest Postgres15 after applying the 4.1.1.30 or 4.1.0.50 FPs above. Instructions to do that can be found here:                             4.1.0.50 post-update instructions: https://www.ibm.com/support/pages/node/7283819           4.1.1.30 post-update instructions: https://www.ibm.com/support/pages/node/7283823

OpenCVE Recommended Actions

  • Download and install the appropriate IBM Service Pack or Fix Pack from Fix Central for the specific AIX or VIOS version that you run.
  • Use Live Update on AIX or perform the required LPAR reboot on VIOS to fully apply the Service Pack or Fix Pack.
  • For VIOS 4.1.0 and 4.1.1, follow the IBM instructions to migrate to Postgres15 after applying the 4.1.0.50 or 4.1.1.30 Fix Pack before the system restarts.

Generated by OpenCVE AI on August 25, 2026 at 17:38 UTC.

Tracking

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Advisories

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History

Tue, 25 Aug 2026 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Ibm vios
Weaknesses CWE-191
CPEs cpe:2.3:a:ibm:vios:*:*:*:*:*:*:*:*
cpe:2.3:o:ibm:aix:*:*:*:*:*:*:*:*
Vendors & Products Ibm vios

Fri, 21 Aug 2026 12:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Thu, 20 Aug 2026 22:00:00 +0000

Type Values Removed Values Added
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.
Title Vulnerabilities in IBM AIX and PowerVM VIOS
First Time appeared Ibm
Ibm aix
Ibm powervm Vios
Weaknesses CWE-787
CPEs cpe:2.3:a:ibm:aix:7.2.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:aix:7.2:*:*:*:*:*:*:*
cpe:2.3:a:ibm:aix:7.3.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:aix:7.3:*:*:*:*:*:*:*
cpe:2.3:a:ibm:powervm_vios:4.1.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:powervm_vios:4.1:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm aix
Ibm powervm Vios
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

Subscriptions

Ibm Aix Powervm Vios Vios
cve-icon MITRE

Status: PUBLISHED

Assigner: ibm

Published:

Updated: 2026-08-25T03:55:55.615Z

Reserved: 2026-07-24T09:08:01.130Z

Link: CVE-2026-16996

cve-icon Vulnrichment

Updated: 2026-08-21T11:12:31.561Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-20T22:17:10.483

Modified: 2026-08-25T13:59:12.383

Link: CVE-2026-16996

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-25T17:45:04Z

Weaknesses
  • CWE-191

    Integer Underflow (Wrap or Wraparound)

  • CWE-787

    Out-of-bounds Write