CVE-2026-46014 (GCVE-0-2026-46014)
Vulnerability from cvelistv5
Published
2026-05-27 12:56
Modified
2026-06-14 17:48
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Add missing save/restore handling of LBR MSRs MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So save/restore is completely broken. Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to LBR MSRs from userspace only (as they are read-only MSRs) if LBR virtualization is enabled. Additionally, to correctly restore L1's LBRs while L2 is running, make sure the LBRs are copied from the captured VMCB01 save area in svm_copy_vmrun_state(). Note, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't reported as an MSR to save/restore. Note #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already handles unsupported reads and writes thanks to commit b5e2fec0ebc3 ("KVM: Ignore DEBUGCTL MSRs with no effect") (kvm_do_msr_access() will morph the unsupported userspace write into a nop). [sean: guard with lbrv checks, massage changelog]
References
Impacted products
Vendor Product Version
Linux Linux Version: 24e09cbf480a72f9c952af4ca77b159503dca44b
Version: 24e09cbf480a72f9c952af4ca77b159503dca44b
Version: 24e09cbf480a72f9c952af4ca77b159503dca44b
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/nested.c",
            "arch/x86/kvm/svm/svm.c",
            "arch/x86/kvm/x86.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2b922a42b531a82d7881add14a7698dcdc5e1f0a",
              "status": "affected",
              "version": "24e09cbf480a72f9c952af4ca77b159503dca44b",
              "versionType": "git"
            },
            {
              "lessThan": "13a89ada5dcfc2539514c83ba5a2c61157f1ec6c",
              "status": "affected",
              "version": "24e09cbf480a72f9c952af4ca77b159503dca44b",
              "versionType": "git"
            },
            {
              "lessThan": "3700f0788da6acf73b2df56690f4b201aa4aefd2",
              "status": "affected",
              "version": "24e09cbf480a72f9c952af4ca77b159503dca44b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/nested.c",
            "arch/x86/kvm/svm/svm.c",
            "arch/x86/kvm/x86.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.26"
            },
            {
              "lessThan": "2.6.26",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.27",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.27",
                  "versionStartIncluding": "2.6.26",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "2.6.26",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "2.6.26",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u0027s 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\u0027t\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]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:48:02.847Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2b922a42b531a82d7881add14a7698dcdc5e1f0a"
        },
        {
          "url": "https://git.kernel.org/stable/c/13a89ada5dcfc2539514c83ba5a2c61157f1ec6c"
        },
        {
          "url": "https://git.kernel.org/stable/c/3700f0788da6acf73b2df56690f4b201aa4aefd2"
        }
      ],
      "title": "KVM: SVM: Add missing save/restore handling of LBR MSRs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46014",
    "datePublished": "2026-05-27T12:56:16.052Z",
    "dateReserved": "2026-05-13T15:03:33.092Z",
    "dateUpdated": "2026-06-14T17:48:02.847Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.