CVE-2026-18840: Vulnerabilities in IBM AIX and PowerVM VIOS

Q: What access would an attacker need to exploit this issue?

The issue is described as locally exploitable, so an attacker would need local access to an affected IBM AIX or IBM PowerVM VIOS system.

Published Aug 15, 2026

Updated

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to execute arbitrary code due to improper validation of an attacker-controlled pointer.

Affected Software

10 affected components

IBM AIX<=7.2

IBM AIX<=7.3

IBM PowerVM VIOS<=4.1

IBM VIOS>=4.1.0<4.1.0.50

IBM VIOS>=4.1.1.0<4.1.1.30

IBM VIOS>=4.1.2.0<4.1.2.20

IBM AIX>=7.2.5<=7.2.5.212

IBM AIX>=7.3.2<=7.3.2.5

IBM AIX>=7.3.3<=7.3.3.2

IBM AIX>=7.3.4<=7.3.4.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade IBM AIX 7.2 to a version that resolves this vulnerability.
Fixed in SP13
Upgrade
Upgrade IBM AIX 7.3 TL04 to a version that resolves this vulnerability.
Fixed in SP2
Upgrade
Upgrade IBM AIX 7.3 TL03 to a version that resolves this vulnerability.
Fixed in SP3
Upgrade
Upgrade IBM AIX 7.3 TL02 to a version that resolves this vulnerability.
Fixed in SP5
Upgrade
Upgrade IBM PowerVM VIOS 4.1.0 to a version that resolves this vulnerability.
Fixed in 4.1.0.50Patch key_w_apar
Upgrade
Upgrade IBM PowerVM VIOS 4.1.1 to a version that resolves this vulnerability.
Fixed in 4.1.1.30Patch key_w_apar
Upgrade
Upgrade IBM PowerVM VIOS 4.1.2 to a version that resolves this vulnerability.
Fixed in 4.1.2.20Patch key_w_apar
Compensating control
For VIOS 4.1.0 and 4.1.1: perform the additional required steps to migrate to the latest Postgres15 after applying the 4.1.0.50 or 4.1.1.30 Fix Packs.
Operational
Reboot the LPAR after completing the SP/FP update to complete the update (an LPAR reboot is required to complete the SP/FP update).
Operational
If using nimsh secure to apply these patches, follow the special steps noted in the provided IBM instructions because the protocol between master and client is updated to be more secure.

Event History

Aug 15, 2026

CVE Published

via IBM·12:00 AM

Data Sourced

via IBM·12:00 AM

DescriptionAffected Software

Aug 20, 2026

CVE Published

via MITRE·10:02 PM

Data Sourced

via MITRE·10:02 PM

RemedyDescriptionSeverityWeakness

Data Sourced

via NVD·10:17 PM

RemedyDescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

IBM-7283858

Frequently Asked Questions

What access would an attacker need to exploit this issue?

The issue is described as locally exploitable, so an attacker would need local access to an affected IBM AIX or IBM PowerVM VIOS system.

CVE-2026-18840: Vulnerabilities in IBM AIX and PowerVM VIOS

Affected Software

Remediation

Event History

Parent advisories

Frequently Asked Questions

What access would an attacker need to exploit this issue?

Company

Resources

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