CVE-2026-16834Network attack vector

Remote service interruption via integer underflow

Published Aug 19, 2026 · Updated Aug 20, 2026

Integer underflow in IBM AIX 7.2 and 7.3 and IBM PowerVM Virtual I/O Server 4.1 allows remote attackers to interrupt service via network requests. IBM's bulletin and the CVE record do not identify the affected component or the arithmetic operation that underflows on untrusted input, so the concrete crash path is undisclosed. Reachability is network-based and requires no authentication according to IBM's published CVSS vector, but the vendor's prose describes denial of service and does not explain whether the flaw has effects beyond service interruption.

CVSS severity9.8
Critical
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in IBM AIX 7.2 and 7.3 and IBM PowerVM Virtual I/O Server 4.1 allows remote attackers to interrupt service via network requests. IBM's bulletin and the CVE record do not identify the affected component or the arithmetic operation that underflows on untrusted input, so the concrete crash path is undisclosed. Reachability is network-based and requires no authentication according to IBM's published CVSS vector, but the vendor's prose describes denial of service and does not explain whether the flaw has effects beyond service interruption.

The record

CVE
CVE-2026-16834
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
OpenBMC Project
Product
AIX
Classifications
CWE-190, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

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

Published CVSS scores

9.8IBM CorporationCVSS:3.1/AV:N/AC:L/PR:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499Endpoint Denial of Service

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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