ghsa-92f6-rh29-hfq6
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Check instead of asserting on nested TSC scaling support
Check for nested TSC scaling support on nested SVM VMRUN instead of asserting that TSC scaling is exposed to L1 if L1's MSR_AMD64_TSC_RATIO has diverged from KVM's default. Userspace can trigger the WARN at will by writing the MSR and then updating guest CPUID to hide the feature (modifying guest CPUID is allowed anytime before KVM_RUN). E.g. hacking KVM's state_test selftest to do
vcpu_set_msr(vcpu, MSR_AMD64_TSC_RATIO, 0);
vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_TSCRATEMSR);
after restoring state in a new VM+vCPU yields an endless supply of:
------------[ cut here ]------------ WARNING: CPU: 164 PID: 62565 at arch/x86/kvm/svm/nested.c:699 nested_vmcb02_prepare_control+0x3d6/0x3f0 [kvm_amd] Call Trace: enter_svm_guest_mode+0x114/0x560 [kvm_amd] nested_svm_vmrun+0x260/0x330 [kvm_amd] vmrun_interception+0x29/0x30 [kvm_amd] svm_invoke_exit_handler+0x35/0x100 [kvm_amd] svm_handle_exit+0xe7/0x180 [kvm_amd] kvm_arch_vcpu_ioctl_run+0x1eab/0x2570 [kvm] kvm_vcpu_ioctl+0x4c9/0x5b0 [kvm] __se_sys_ioctl+0x7a/0xc0 __x64_sys_ioctl+0x21/0x30 do_syscall_64+0x41/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x45ca1b
Note, the nested #VMEXIT path has the same flaw, but needs a different fix and will be handled separately.
{
"affected": [],
"aliases": [
"CVE-2023-53663"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-07T16:15:50Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Check instead of asserting on nested TSC scaling support\n\nCheck for nested TSC scaling support on nested SVM VMRUN instead of\nasserting that TSC scaling is exposed to L1 if L1\u0027s MSR_AMD64_TSC_RATIO\nhas diverged from KVM\u0027s default. Userspace can trigger the WARN at will\nby writing the MSR and then updating guest CPUID to hide the feature\n(modifying guest CPUID is allowed anytime before KVM_RUN). E.g. hacking\nKVM\u0027s state_test selftest to do\n\n\t\tvcpu_set_msr(vcpu, MSR_AMD64_TSC_RATIO, 0);\n\t\tvcpu_clear_cpuid_feature(vcpu, X86_FEATURE_TSCRATEMSR);\n\nafter restoring state in a new VM+vCPU yields an endless supply of:\n\n ------------[ cut here ]------------\n WARNING: CPU: 164 PID: 62565 at arch/x86/kvm/svm/nested.c:699\n nested_vmcb02_prepare_control+0x3d6/0x3f0 [kvm_amd]\n Call Trace:\n \u003cTASK\u003e\n enter_svm_guest_mode+0x114/0x560 [kvm_amd]\n nested_svm_vmrun+0x260/0x330 [kvm_amd]\n vmrun_interception+0x29/0x30 [kvm_amd]\n svm_invoke_exit_handler+0x35/0x100 [kvm_amd]\n svm_handle_exit+0xe7/0x180 [kvm_amd]\n kvm_arch_vcpu_ioctl_run+0x1eab/0x2570 [kvm]\n kvm_vcpu_ioctl+0x4c9/0x5b0 [kvm]\n __se_sys_ioctl+0x7a/0xc0\n __x64_sys_ioctl+0x21/0x30\n do_syscall_64+0x41/0x90\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n RIP: 0033:0x45ca1b\n\nNote, the nested #VMEXIT path has the same flaw, but needs a different\nfix and will be handled separately.",
"id": "GHSA-92f6-rh29-hfq6",
"modified": "2025-10-07T18:31:10Z",
"published": "2025-10-07T18:31:10Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53663"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/02b24270568f65dd607c4a848512dc8055b4491b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6c1ecfea1daf6e75c46e295aad99dfbafd878897"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7cafe9b8e22bb3d77f130c461aedf6868c4aaf58"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
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