CVE-2026-18821

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

CVE-2026-18821 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

CVE-2026-18821 affects products from ibm, specifically: power_system_e1050_\(9043-mrx\), power_system_e1050_\(9043-mrx\)_firmware, power_system_e1080_\(9080-hex\), power_system_e1080_\(9080-hex\)_firmware, power_system_e1150_\(9043-mru\), power_system_e1150_\(9043-mru\)_firmware, power_system_e1180_\(9080-heu\), power_system_e1180_\(9080-heu\)_firmware, power_system_e950_\(9040-mr9\), power_system_e950_\(9040-mr9\)_firmware, power_system_e980_\(9080-m9s\), power_system_e980_\(9080-m9s\)_firmware, power_system_h922_\(9223-22s\), power_system_h922_\(9223-22s\)_firmware, power_system_h924_\(9223-42s\), power_system_h924_\(9223-42s\)_firmware, power_system_l1022_\(9786-22h\), power_system_l1022_\(9786-22h\)_firmware, power_system_l1024_\(9786-42h\), power_system_l1024_\(9786-42h\)_firmware, power_system_l1122_\(9856-22h\), power_system_l1122_\(9856-22h\)_firmware, power_system_l1124_\(9856-42h\), power_system_l1124_\(9856-42h\)_firmware, power_system_s1012_\(9028-21b\), power_system_s1012_\(9028-21b\)_firmware, power_system_s1014_\(9105-41b\), power_system_s1014_\(9105-41b\)_firmware, power_system_s1022_\(9105-22a\), power_system_s1022_\(9105-22a\)_firmware, power_system_s1022s_\(9105-22b\), power_system_s1022s_\(9105-22b\)_firmware, power_system_s1024_\(9105-42a\), power_system_s1024_\(9105-42a\)_firmware, power_system_s1112_\(9242-21b\), power_system_s1112_\(9242-21b\)_firmware, power_system_s1112_\(9242-21t\), power_system_s1112_\(9242-21t\)_firmware, power_system_s1114_\(9824-41b\), power_system_s1114_\(9824-41b\)_firmware, power_system_s1122_\(9824-22a\), power_system_s1122_\(9824-22a\)_firmware, power_system_s1122s_\(9824-22b\), power_system_s1122s_\(9824-22b\)_firmware, power_system_s1124_\(9824-42a\), power_system_s1124_\(9824-42a\)_firmware, power_system_s914_\(9009-41g\), power_system_s914_\(9009-41g\)_firmware, power_system_s922_\(9009-22g\), power_system_s922_\(9009-22g\)_firmware, power_system_s924_\(9009-42g\), power_system_s924_\(9009-42g\)_firmware. Check the affected products table above for specific version ranges.

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.