CVE-2026-89921

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux383d0b050106abecb82f43101cac94fa423af5cd < 9b046de62b8098af6e2ba820b125ec9dc5f162c8affected
LinuxLinux383d0b050106abecb82f43101cac94fa423af5cd < 134f235e0e8de54611a72d3cc3f63e5f31246baaaffected
LinuxLinux383d0b050106abecb82f43101cac94fa423af5cd < 4e2c7f7cbc27418f9a290399b986c1b85ff93b90affected
LinuxLinux3.19affected
LinuxLinux0 < 3.19unaffected
LinuxLinux6.18.52 <= 6.18.*unaffected
LinuxLinux7.2.5 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References