{"id":"CVE-2026-23425","summary":"KVM: arm64: Fix ID register initialization for non-protected pKVM guests","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Fix ID register initialization for non-protected pKVM guests\n\nIn protected mode, the hypervisor maintains a separate instance of\nthe `kvm` structure for each VM. For non-protected VMs, this structure is\ninitialized from the host's `kvm` state.\n\nCurrently, `pkvm_init_features_from_host()` copies the\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the\nunderlying `id_regs` data being initialized. This results in the\nhypervisor seeing the flag as set while the ID registers remain zeroed.\n\nConsequently, `kvm_has_feat()` checks at EL2 fail (return 0) for\nnon-protected VMs. This breaks logic that relies on feature detection,\nsuch as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain\nsystem registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not\nsaved/restored during the world switch, which could lead to state\ncorruption.\n\nFix this by explicitly copying the ID registers from the host `kvm` to\nthe hypervisor `kvm` for non-protected VMs during initialization, since\nwe trust the host with its non-protected guests' features. Also ensure\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in\n`pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly\ninitialize them and set the flag once done.","modified":"2026-05-07T04:17:27.139057Z","published":"2026-04-03T13:24:33.384Z","related":["SUSE-SU-2026:21237-1","SUSE-SU-2026:21352-1","SUSE-SU-2026:21361-1","openSUSE-SU-2026:20572-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23425.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17"},{"type":"WEB","url":"https://git.kernel.org/stable/c/858620655c1fbff05997e162fc7d83a3293d5142"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bce3847f7c51b86332bf2e554c9e80ca3820f16c"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23425.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23425"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"41d6028e28bd474298ff10409c292ec46cf43a90"},{"fixed":"bce3847f7c51b86332bf2e554c9e80ca3820f16c"},{"fixed":"858620655c1fbff05997e162fc7d83a3293d5142"},{"fixed":"7e7c2cf0024d89443a7af52e09e47b1fe634ab17"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23425.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.14.0"},{"fixed":"6.18.17"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23425.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}