{"cve":"CVE-2023-53663","nvd":{"published":"2025-10-07T16:15:50.043","modified":"2026-06-17T06:45:49.430","status":"Analyzed","description":"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's MSR_AMD64_TSC_RATIO\nhas diverged from KVM's 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's 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   <TASK>\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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/02b24270568f65dd607c4a848512dc8055b4491b","https://git.kernel.org/stable/c/6c1ecfea1daf6e75c46e295aad99dfbafd878897","https://git.kernel.org/stable/c/7cafe9b8e22bb3d77f130c461aedf6868c4aaf58"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:11:26.888974865+00:00"},"epss":{"cve":"CVE-2023-53663","score":0.00146,"percentile":0.03862,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}