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CVE-2026-16687NVD status: Analyzed

Power Systems Firmware: Stack-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-16687 is a critical-severity stack-based buffer overflow vulnerability in Power Systems Firmware from IBM, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected Power Systems Firmware versions: FW1120.00; FW1110.00 through FW1110.30; FW1060.00 through FW1060.80, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.35% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Power System E1180 (9080-heu) Firmware to fw1110.31 or a later version.
  2. Update Power System E1080 (9080-hex) Firmware to fw1060.81 or a later version.
  3. Update Power System S922 (9009-22g) Firmware to fw950.h3 or a later version.
  4. Read the advisory on ibm.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
IBMPower Systems FirmwareFW1120.00; FW1110.00 through FW1110.30; FW1060.00 through FW1060.80; FW950.00 through FW950.H2Not stated
IBMPower System E1180 (9080-heu) Firmwarefw1110.00 up to, but not including, fw1110.31; fw1120.00fw1110.31
IBMPower System E1080 (9080-hex) Firmwarefw1060.00 up to, but not including, fw1060.81fw1060.81
IBMPower System S922 (9009-22g) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System H922 (9223-22s) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System S914 (9009-41g) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System S924 (9009-42g) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System H924 (9223-42s) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System E950 (9040-mr9) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3
IBMPower System E980 (9080-m9s) Firmwarefw950.00 up to, but not including, fw950.h3fw950.h3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (us.ibm.com).

Official description

IBM Power Systems Firmware FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, and FW950.00 through FW950.H2 is affected by a vulnerability in the ASMI web interface. An unauthenticated attacker with network access can send the FSP a malformed request, allowing arbitrary code execution, giving the attacker full control over the managed system, resulting in a confidentiality, integrity, and availability impact.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Stack-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the stack.

How developers prevent this class of flaw

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Implement and perform bounds checking on input.

More Stack-based Buffer Overflow vulnerabilities (CWE-121)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Power Systems Firmware

All Power Systems Firmware vulnerabilities

Recent Stack-based Buffer Overflow vulnerabilities

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