CVE-2026-89921

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Zero initialize data structures for inject_pfault_token __kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of the on-stack struct kvm_s390_irq but the full ext substructure is copied into the cpu local variable on inject. ext_params and pad contain stale stack values. Interrupt delivery only uses ext_params2, so nothing leaks to the guest, but a host user can use the migration ioctls to get to the data. Fix by zero-initializing the irq struct. Do the same for the inti data structure.

• https://git.kernel.org/stable/c/134f235e0e8de54611a72d3cc3f63e5f31246baa
• https://git.kernel.org/stable/c/4e2c7f7cbc27418f9a290399b986c1b85ff93b90
• https://git.kernel.org/stable/c/9b046de62b8098af6e2ba820b125ec9dc5f162c8