CVE-2026-16687

Unauthenticated code execution via malformed ASMI request

Published Aug 19, 2026 · Updated Aug 20, 2026

Stack-based buffer overflow in IBM Power Systems Firmware allows remote attackers to execute code through a malformed ASMI request. The affected ASMI web-interface handler accepts the malformed request at the FSP, but IBM has not disclosed the specific handler or unchecked copy operation. Unauthenticated management-network access is sufficient; exploitation grants full control of the managed system, including its data, configuration, and availability.

CVSS severity9.6
Critical
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in IBM Power Systems Firmware allows remote attackers to execute code through a malformed ASMI request. The affected ASMI web-interface handler accepts the malformed request at the FSP, but IBM has not disclosed the specific handler or unchecked copy operation. Unauthenticated management-network access is sufficient; exploitation grants full control of the managed system, including its data, configuration, and availability.

The record

CVE
CVE-2026-16687
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
IBM
Product
Power Systems Firmware
Classifications
CWE-121, T1190
Attack vector
adjacent
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=FW1060.00 <=FW1060.80
  2. Affected versionversion=FW1110.00 <=FW1110.30
  3. Affected versionversion=FW1120.00
  4. Affected versionversion=FW950.00 <=FW950.H2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

IBM · Power Systems Firmwareversion=FW1060.00 <=FW1060.80; version=FW1110.00 <=FW1110.30; version=FW1120.00; version=FW950.00 <=FW950.H2

Published CVSS scores

9.6IBMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
T1190Exploit Public-Facing Application

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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