CVE-2026-17121Network attack vector

Unauthenticated service interruption via uncontrolled recursion

Published Aug 20, 2026 · Updated Aug 20, 2026

Uncontrolled recursion in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows remote attackers to interrupt service over the network. The affected bos.mp64 fileset enters uncontrolled recursion, but IBM has not disclosed the specific request-processing path or malformed input that triggers it. No authentication or user interaction is required, and successful exploitation makes the affected system unavailable without reported data access or modification.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in IBM AIX 7.2 and 7.3 and PowerVM VIOS 4.1 allows remote attackers to interrupt service over the network. The affected bos.mp64 fileset enters uncontrolled recursion, but IBM has not disclosed the specific request-processing path or malformed input that triggers it. No authentication or user interaction is required, and successful exploitation makes the affected system unavailable without reported data access or modification.

The record

CVE
CVE-2026-17121
Published
Aug 20, 2026
Updated
Aug 20, 2026
Vendor
IBM
Product
AIX
Classifications
CWE-674, CWE-400, T1499
Attack vector
network
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 vectornetwork
Required privilegesunauthenticated

What is affected?

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

Published CVSS scores

7.5IBM CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 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-674Uncontrolled Recursion
CWE-400Uncontrolled Resource Consumption
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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