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Fencer Intel
high 7.5

CVE-2026-18821 json

Power System Out-of-bounds Write

published 2mo ago modified 2mo ago also EUVD-2026-62876

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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.

Patch / fix

  • ibm power_system_s1122_(9824-22a)_firmware fw1110.31
  • ibm power_system_s1124_(9824-42a)_firmware fw1110.31
  • ibm power_system_s1122s_(9824-22b)_firmware fw1110.31
  • ibm power_system_s1114_(9824-41b)_firmware fw1110.31
  • ibm power_system_l1122_(9856-22h)_firmware fw1110.31
  • ibm power_system_l1124_(9856-42h)_firmware fw1110.31
  • ibm power_system_e1150_(9043-mru)_firmware fw1110.31
  • ibm power_system_e1080_(9080-hex)_firmware fw1060.81
  • ibm power_system_s1022_(9105-22a)_firmware fw1060.81
  • ibm power_system_s1024_(9105-42a)_firmware fw1060.81
  • ibm power_system_s1022s_(9105-22b)_firmware fw1060.81
  • ibm power_system_s1014_(9105-41b)_firmware fw1060.81
  • ibm power_system_l1022_(9786-22h)_firmware fw1060.81
  • ibm power_system_l1024_(9786-42h)_firmware fw1060.81
  • ibm power_system_e1050_(9043-mrx)_firmware fw1060.81
  • ibm power_system_s1012_(9028-21b)_firmware fw1060.81
  • ibm power_system_e1180_(9080-heu)_firmware fw1110.31
  • ibm power_system_s922_(9009-22g)_firmware fw950.h3
  • ibm power_system_h922_(9223-22s)_firmware fw950.h3
  • ibm power_system_s914_(9009-41g)_firmware fw950.h3

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • IBM PowerVM Hypervisor

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.