cbcvebase.
CVE-2026-23425
published 2026-04-03

CVE-2026-23425: In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for non-protected pKVM guests In protected mode…

PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.12%
2.1th percentile
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for non-protected pKVM guests In protected mode, the hypervisor maintains a separate instance of the `kvm` structure for each VM. For non-protected VMs, this structure is initialized from the host's `kvm` state. Currently, `pkvm_init_features_from_host()` copies the `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the underlying `id_regs` data being initialized. This results in the hypervisor seeing the flag as set while the ID registers remain zeroed. Consequently, `kvm_has_feat()` checks at EL2 fail (return 0) for non-protected VMs. This breaks logic that relies on feature detection, such as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain system registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not saved/restored during the world switch, which could lead to state corruption. Fix this by explicitly copying the ID registers from the host `kvm` to the hypervisor `kvm` for non-protected VMs during initialization, since we trust the host with its non-protected guests' features. Also ensure `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in `pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly initialize them and set the flag once done.

Affected

16 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.19.8-1 (forky)linux 6.19.8-1 (forky)
linuxlinux
linuxlinux>= 41d6028e28bd474298ff10409c292ec46cf43a90 < bce3847f7c51b86332bf2e554c9e80ca3820f16cbce3847f7c51b86332bf2e554c9e80ca3820f16c
linuxlinux>= 41d6028e28bd474298ff10409c292ec46cf43a90 < 858620655c1fbff05997e162fc7d83a3293d5142858620655c1fbff05997e162fc7d83a3293d5142
linuxlinux>= 41d6028e28bd474298ff10409c292ec46cf43a90 < 7e7c2cf0024d89443a7af52e09e47b1fe634ab177e7c2cf0024d89443a7af52e09e47b1fe634ab17
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.19.8-16.19.8-1
linuxlinux_kernel>= 6.14.1 < 6.18.176.18.17
linuxlinux_kernel>= 6.19 < 6.19.76.19.7
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