CVE-2026-18842

Local privilege escalation via out-of-bounds write

Published Aug 20, 2026 · Updated Aug 20, 2026

Out-of-bounds write in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows local users to gain elevated privileges. IBM identifies no affected component or input path, disclosing only that an out-of-bounds write causes the privilege escalation. Local execution is required, but IBM does not identify the resulting privilege level or whether the flaw can be tested without altering the system.

CVSS severity8.4
High
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows local users to gain elevated privileges. IBM identifies no affected component or input path, disclosing only that an out-of-bounds write causes the privilege escalation. Local execution is required, but IBM does not identify the resulting privilege level or whether the flaw can be tested without altering the system.

The record

CVE
CVE-2026-18842
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
IBM
Product
AIX
Classifications
CWE-787, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.2
  2. Affected versionversion=7.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

IBM · AIXversion=7.2; version=7.3
IBM · PowerVM Virtual I/O Serverversion=4.1

Published CVSS scores

8.4IBMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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