# CVE-2026-18842: IBM AIX and PowerVM VIOS out-of-bounds write privilege escalation

Source: https://junglewise.ai/threats/cve-2026-18842-ibm-aix-and-powervm-vios-out-of-bounds-write-privilege-escalation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-20. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-18842 · Severity: high · CVSS 8.4 · Published 2026-08-20

IBM AIX and PowerVM VIOS are operating systems and virtualization platforms used to run enterprise applications. A local attacker who already has access to a system can exploit an out-of-bounds write vulnerability to gain elevated privileges, potentially allowing them to compromise the entire system or access sensitive data.

Technologies: [IBM Aix](https://junglewise.ai/threats/technologies/aix), [IBM PowerVM VIOS](https://junglewise.ai/threats/technologies/powervm-vios). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-18842 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18842 being exploited in the wild.

**How severe is CVE-2026-18842?** High severity, with a CVSS score of 8.4, published 20 August 2026.

**Which products and versions are affected?** IBM Aix 7.2, 7.3; IBM PowerVM VIOS 4.1.

**Is there a fix for CVE-2026-18842?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-18842 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-18842?** Check whether you run IBM Aix or IBM PowerVM VIOS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An out-of-bounds write vulnerability exists in IBM AIX 7.2, 7.3, and IBM PowerVM VIOS 4.1. The vulnerability allows a local attacker to write data beyond the boundaries of an allocated buffer, corrupting memory and potentially enabling arbitrary code execution. The attack requires local access to the system (local attack vector) with standard user privileges. By exploiting this flaw, an attacker can escalate their privileges to gain administrative control. IBM has released security updates in the form of Service Packs (SPs) and Fix Packs (FPs) to address this vulnerability.

## Affected products

- IBM AIX 7.2, 7.3
- IBM PowerVM VIOS 4.1

## Timeline

- 2026-08-20: disclosed

## References

- [https://www.ibm.com/support/pages/node/7283858](https://www.ibm.com/support/pages/node/7283858)

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