# CVE-2026-23425: linux: In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for n... CVE-2026-23425 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2026-23425, released April 3, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-23425 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0012 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 3, 2026 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.27.1.160000.2.8 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-livepatch-6.18.20-20.229 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.28.1 | [OPENSUSE-SU-2026:20572-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20572-1.md) | Apr 20, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-libbpf amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-libbpf-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-libbpf-devel amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-libbpf-static amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | linux Debian 14 | 6.19.8-1 | [DEBIAN-CVE-2026-23425](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23425.md) | Apr 3, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.20-20.229.amzn2023 | [ALAS2023-2026-1596](https://patchblox.com/security/data/fix/linux/alas2023-2026-1596.md) | Apr 27, 2026 | --- Data as of 2026-11-09T07:25:28Z UTC. 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