IBM PowerVM Hypervisor (FW1120: Network Boot RCE)
CVE-2026-18821 Published on August 19, 2026
Power System Out-of-bounds Write
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.
Vulnerability Analysis
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-18821 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-18821
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Affected Versions
IBM PowerVM Hypervisor:- Version FW1120.00 is affected.
- Version FW1110.00, <= FW1110.30 is affected.
- Version FW1060.00, <= FW1060.80 is affected.
- Version FW950.00, <= FW950.H2 is affected.