CVE-2026-18821
Analyzed Analyzed - Analysis Complete

IBM PowerVM Hypervisor Firmware Network Boot Code Execution

Publication date: 2026-08-19

Last updated on: 2026-08-25

Assigner: IBM Corporation

Description
IBM PowerVM Hypervisor FW1120.00, FW1110.00 through FW1110.30, FW1060.00 through FW1060.80, and FW950.00 through FW950.H2 Power Systems Firmware is affected by a vulnerability in partition firmware during network boot. An unauthenticated attacker on the same network as a partition undergoing network boot can send a malformed packet, allowing arbitrary code to be executed in the partition firmware and compromising everything subsequently loaded by that partition. Other partitions and the managed system are not affected. Only partitions actively performing a network boot are affected, resulting in a confidentiality, integrity, and availability impact.

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Meta Information

Published
2026-08-19
Last Modified
2026-08-25
Generated
2026-09-09
AI Q&A
2026-08-19
EPSS Evaluated
2026-09-07
NVD
CVE-2026-18821
EUVD
EUVD-2026-62876

Affected Vendors & Products

Showing 34 associated CPEs
Vendor Product Version / Range
ibm power_system_s1122_(9824-22a)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_s1122_(9824-22a)_firmware fw1120.00
ibm power_system_s1124_(9824-42a)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_s1124_(9824-42a)_firmware fw1120.00
ibm power_system_s1122s_(9824-22b)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_s1122s_(9824-22b)_firmware fw1120.00
ibm power_system_s1114_(9824-41b)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_s1114_(9824-41b)_firmware fw1120.00
ibm power_system_l1122_(9856-22h)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_l1122_(9856-22h)_firmware fw1120.00
ibm power_system_l1124_(9856-42h)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_l1124_(9856-42h)_firmware fw1120.00
ibm power_system_e1150_(9043-mru)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_e1150_(9043-mru)_firmware fw1120.00
ibm power_system_s1112_(9242-21b)_firmware fw1120.00
ibm power_system_s1112_(9242-21t)_firmware fw1120.00
ibm power_system_e1080_(9080-hex)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_s1022_(9105-22a)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_s1024_(9105-42a)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_s1022s_(9105-22b)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_s1014_(9105-41b)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_l1022_(9786-22h)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_l1024_(9786-42h)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_e1050_(9043-mrx)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_s1012_(9028-21b)_firmware From fw1060.00 (inc) to fw1060.81 (exc)
ibm power_system_e1180_(9080-heu)_firmware From fw1110.00 (inc) to fw1110.31 (exc)
ibm power_system_e1180_(9080-heu)_firmware fw1120.00
ibm power_system_s922_(9009-22g)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_h922_(9223-22s)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_s914_(9009-41g)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_s924_(9009-42g)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_h924_(9223-42s)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_e950_(9040-mr9)_firmware From fw950.00 (inc) to fw950.h3 (exc)
ibm power_system_e980_(9080-m9s)_firmware From fw950.00 (inc) to fw950.h3 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.

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Executive Summary

CVE-2026-18821 is a vulnerability in IBM PowerVM Hypervisor firmware affecting partition firmware during network boot. An unauthenticated attacker on the same network as a partition performing a network boot can send a malformed packet to execute arbitrary code in the partition firmware. This compromises everything loaded by that partition, impacting confidentiality, integrity, and availability.

Detection Guidance

Detecting this vulnerability requires monitoring network traffic during partition network boot operations. Check for malformed packets sent to the booting partition's IP address. Use network sniffing tools like tcpdump or Wireshark to capture boot-related traffic and look for anomalies in DHCP, TFTP, or PXE protocols during boot sequences.

Impact Analysis

If you are using affected IBM Power Systems firmware versions, an attacker on the same network could exploit this during a network boot to execute arbitrary code in the partition firmware. This could lead to unauthorized access, data breaches, system crashes, or further compromise of the partition's operating system and applications.

Compliance Impact

This vulnerability could lead to unauthorized access and data breaches, which may violate GDPR's data protection requirements or HIPAA's security and privacy rules. Organizations using affected systems may face compliance violations, legal penalties, and reputational damage if exploited.

Mitigation Strategies

Immediately update the firmware of affected Power Systems to the latest versions provided by IBM for Power 9, Power 10, and Power 11 systems. Isolate network segments where partitions perform network boot to limit exposure. Disable network boot for non-essential partitions until patches are applied.

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