This vulnerability originates from an integer overflow in the PowerVM hypervisor call interface. An attacker who has already achieved root privilege inside a guest partition can craft a hypervisor call that injects an arbitrary amount of data into hypervisor or partition memory. The overflow causes either a crash that triggers a full platform re‑IPL, terminating all hosted partitions, or corruption of hypervisor or partition memory. Repeated exploitation can lead to a sustained availability impact, and the integrity of both the hypervisor and user partitions is compromised.

Affected systems are IBM PowerVM firmware releases for Power 9, 10, and 11 platforms. The issue covers firmware series FW950.00 through FW950.H2 for Power 9, FW1060.00 through FW1060.80 for Power 10, and FW1110.00 through FW1110.30 and FW1120.00 for Power 11. Affected product models include IBM Power System E1180, S1122, S1124, S1114, L1122, L1124, E1150, S1112, S1022, S1024, S1014, L1022, L1024, E1050, E1080, S1022s, S1012, S922, H922, S914, S924, H924, E950, and E980.

The vulnerability is assigned a CVSS score of 8.4, categorizing it as high severity. The EPSS score is currently unavailable, but the lack of KEV listing does not diminish the risk of exploitation. Because the attack requires root access in a guest, privilege escalation within a virtual machine is a prerequisite; once achieved, the attacker can trigger a crash or memory corruption, leading to loss of service or compromise of data integrity. The described impact, combined with the high CVSS score, positions this flaw as a significant threat to affected IBM Power systems.