{"cve":"CVE-2026-46014","nvd":{"published":"2026-05-27T14:17:19.667","modified":"2026-10-21T13:19:02.373","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Add missing save/restore handling of LBR MSRs\n\nMSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by\nKVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So\nsave/restore is completely broken.\n\nFix it by adding the MSRs to msrs_to_save_base, and allowing writes to\nLBR MSRs from userspace only (as they are read-only MSRs) if LBR\nvirtualization is enabled.  Additionally, to correctly restore L1's LBRs\nwhile L2 is running, make sure the LBRs are copied from the captured\nVMCB01 save area in svm_copy_vmrun_state().\n\nNote, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't\nreported as an MSR to save/restore.\n\nNote #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already\nhandles unsupported reads and writes thanks to commit b5e2fec0ebc3 (\"KVM:\nIgnore DEBUGCTL MSRs with no effect\") (kvm_do_msr_access() will morph the\nunsupported userspace write into a nop).\n\n[sean: guard with lbrv checks, massage changelog]","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":["CWE-667"],"references":["https://git.kernel.org/stable/c/13a89ada5dcfc2539514c83ba5a2c61157f1ec6c","https://git.kernel.org/stable/c/2b922a42b531a82d7881add14a7698dcdc5e1f0a","https://git.kernel.org/stable/c/3700f0788da6acf73b2df56690f4b201aa4aefd2","https://git.kernel.org/stable/c/4428a0a8643b0acf4ed7b8ea3e5975023bf4aafb","https://git.kernel.org/stable/c/bca0597272f9712b1f8ebd38b184db1dc2902ff7"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-46014","score":0.00095,"percentile":0.00599,"date":"2026-10-25"},"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."]}