CVE-2023-53208 (GCVE-0-2023-53208)

Vulnerability from cvelistv5 – Published: 2025-09-15 14:21 – Updated: 2026-01-14 17:52
VLAI?
Title
KVM: nSVM: Load L1's TSC multiplier based on L1 state, not L2 state
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Load L1's TSC multiplier based on L1 state, not L2 state When emulating nested VM-Exit, load L1's TSC multiplier if L1's desired ratio doesn't match the current ratio, not if the ratio L1 is using for L2 diverges from the default. Functionally, the end result is the same as KVM will run L2 with L1's multiplier if L2's multiplier is the default, i.e. checking that L1's multiplier is loaded is equivalent to checking if L2 has a non-default multiplier. However, the assertion that TSC scaling is exposed to L1 is flawed, as 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: 10 PID: 206939 at arch/x86/kvm/svm/nested.c:1105 nested_svm_vmexit+0x6af/0x720 [kvm_amd] Call Trace: nested_svm_exit_handled+0x102/0x1f0 [kvm_amd] svm_handle_exit+0xb9/0x180 [kvm_amd] kvm_arch_vcpu_ioctl_run+0x1eab/0x2570 [kvm] kvm_vcpu_ioctl+0x4c9/0x5b0 [kvm] ? trace_hardirqs_off+0x4d/0xa0 __se_sys_ioctl+0x7a/0xc0 __x64_sys_ioctl+0x21/0x30 do_syscall_64+0x41/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Unlike the nested VMRUN path, hoisting the svm->tsc_scaling_enabled check into the if-statement is wrong as KVM needs to ensure L1's multiplier is loaded in the above scenario. Alternatively, the WARN_ON() could simply be deleted, but that would make KVM's behavior even more subtle, e.g. it's not immediately obvious why it's safe to write MSR_AMD64_TSC_RATIO when checking only tsc_ratio_msr.
Severity ?
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 5228eb96a4875f8cf5d61d486e3795ac14df8904 , < 5b2b0535fa7adee7e295fed0a3095082131a8d05 (git)
Affected: 5228eb96a4875f8cf5d61d486e3795ac14df8904 , < e91c07f6cf7060d2acb3aeee31a6baebe3773d3f (git)
Affected: 5228eb96a4875f8cf5d61d486e3795ac14df8904 , < 0c94e2468491cbf0754f49a5136ab51294a96b69 (git)
Create a notification for this product.
    Linux Linux Affected: 5.16
Unaffected: 0 , < 5.16 (semver)
Unaffected: 6.1.54 , ≤ 6.1.* (semver)
Unaffected: 6.5.4 , ≤ 6.5.* (semver)
Unaffected: 6.6 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2023-53208",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-14T17:48:02.195989Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "description": "CWE-noinfo Not enough information",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-14T17:52:56.568Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5b2b0535fa7adee7e295fed0a3095082131a8d05",
              "status": "affected",
              "version": "5228eb96a4875f8cf5d61d486e3795ac14df8904",
              "versionType": "git"
            },
            {
              "lessThan": "e91c07f6cf7060d2acb3aeee31a6baebe3773d3f",
              "status": "affected",
              "version": "5228eb96a4875f8cf5d61d486e3795ac14df8904",
              "versionType": "git"
            },
            {
              "lessThan": "0c94e2468491cbf0754f49a5136ab51294a96b69",
              "status": "affected",
              "version": "5228eb96a4875f8cf5d61d486e3795ac14df8904",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.16"
            },
            {
              "lessThan": "5.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.54",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.5.*",
              "status": "unaffected",
              "version": "6.5.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.6",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.54",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.5.4",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6",
                  "versionStartIncluding": "5.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Load L1\u0027s TSC multiplier based on L1 state, not L2 state\n\nWhen emulating nested VM-Exit, load L1\u0027s TSC multiplier if L1\u0027s desired\nratio doesn\u0027t match the current ratio, not if the ratio L1 is using for\nL2 diverges from the default.  Functionally, the end result is the same\nas KVM will run L2 with L1\u0027s multiplier if L2\u0027s multiplier is the default,\ni.e. checking that L1\u0027s multiplier is loaded is equivalent to checking if\nL2 has a non-default multiplier.\n\nHowever, the assertion that TSC scaling is exposed to L1 is flawed, as\nuserspace can trigger the WARN at will by writing the MSR and then\nupdating guest CPUID to hide the feature (modifying guest CPUID is\nallowed anytime before KVM_RUN).  E.g. hacking KVM\u0027s state_test\nselftest to do\n\n                vcpu_set_msr(vcpu, MSR_AMD64_TSC_RATIO, 0);\n                vcpu_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: 10 PID: 206939 at arch/x86/kvm/svm/nested.c:1105\n           nested_svm_vmexit+0x6af/0x720 [kvm_amd]\n  Call Trace:\n   nested_svm_exit_handled+0x102/0x1f0 [kvm_amd]\n   svm_handle_exit+0xb9/0x180 [kvm_amd]\n   kvm_arch_vcpu_ioctl_run+0x1eab/0x2570 [kvm]\n   kvm_vcpu_ioctl+0x4c9/0x5b0 [kvm]\n   ? trace_hardirqs_off+0x4d/0xa0\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\nUnlike the nested VMRUN path, hoisting the svm-\u003etsc_scaling_enabled check\ninto the if-statement is wrong as KVM needs to ensure L1\u0027s multiplier is\nloaded in the above scenario.   Alternatively, the WARN_ON() could simply\nbe deleted, but that would make KVM\u0027s behavior even more subtle, e.g. it\u0027s\nnot immediately obvious why it\u0027s safe to write MSR_AMD64_TSC_RATIO when\nchecking only tsc_ratio_msr."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-09-15T14:21:36.170Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5b2b0535fa7adee7e295fed0a3095082131a8d05"
        },
        {
          "url": "https://git.kernel.org/stable/c/e91c07f6cf7060d2acb3aeee31a6baebe3773d3f"
        },
        {
          "url": "https://git.kernel.org/stable/c/0c94e2468491cbf0754f49a5136ab51294a96b69"
        }
      ],
      "title": "KVM: nSVM: Load L1\u0027s TSC multiplier based on L1 state, not L2 state",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53208",
    "datePublished": "2025-09-15T14:21:36.170Z",
    "dateReserved": "2025-09-15T13:59:19.068Z",
    "dateUpdated": "2026-01-14T17:52:56.568Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2023-53208\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-01-14T17:48:02.195989Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"description\": \"CWE-noinfo Not enough information\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-01-14T17:47:57.017Z\"}}], \"cna\": {\"title\": \"KVM: nSVM: Load L1\u0027s TSC multiplier based on L1 state, not L2 state\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5228eb96a4875f8cf5d61d486e3795ac14df8904\", \"lessThan\": \"5b2b0535fa7adee7e295fed0a3095082131a8d05\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"5228eb96a4875f8cf5d61d486e3795ac14df8904\", \"lessThan\": \"e91c07f6cf7060d2acb3aeee31a6baebe3773d3f\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"5228eb96a4875f8cf5d61d486e3795ac14df8904\", \"lessThan\": \"0c94e2468491cbf0754f49a5136ab51294a96b69\", \"versionType\": \"git\"}], \"programFiles\": [\"arch/x86/kvm/svm/nested.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.16\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.16\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.1.54\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.5.4\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.5.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"arch/x86/kvm/svm/nested.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/5b2b0535fa7adee7e295fed0a3095082131a8d05\"}, {\"url\": \"https://git.kernel.org/stable/c/e91c07f6cf7060d2acb3aeee31a6baebe3773d3f\"}, {\"url\": \"https://git.kernel.org/stable/c/0c94e2468491cbf0754f49a5136ab51294a96b69\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nKVM: nSVM: Load L1\u0027s TSC multiplier based on L1 state, not L2 state\\n\\nWhen emulating nested VM-Exit, load L1\u0027s TSC multiplier if L1\u0027s desired\\nratio doesn\u0027t match the current ratio, not if the ratio L1 is using for\\nL2 diverges from the default.  Functionally, the end result is the same\\nas KVM will run L2 with L1\u0027s multiplier if L2\u0027s multiplier is the default,\\ni.e. checking that L1\u0027s multiplier is loaded is equivalent to checking if\\nL2 has a non-default multiplier.\\n\\nHowever, the assertion that TSC scaling is exposed to L1 is flawed, as\\nuserspace can trigger the WARN at will by writing the MSR and then\\nupdating guest CPUID to hide the feature (modifying guest CPUID is\\nallowed anytime before KVM_RUN).  E.g. hacking KVM\u0027s state_test\\nselftest to do\\n\\n                vcpu_set_msr(vcpu, MSR_AMD64_TSC_RATIO, 0);\\n                vcpu_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: 10 PID: 206939 at arch/x86/kvm/svm/nested.c:1105\\n           nested_svm_vmexit+0x6af/0x720 [kvm_amd]\\n  Call Trace:\\n   nested_svm_exit_handled+0x102/0x1f0 [kvm_amd]\\n   svm_handle_exit+0xb9/0x180 [kvm_amd]\\n   kvm_arch_vcpu_ioctl_run+0x1eab/0x2570 [kvm]\\n   kvm_vcpu_ioctl+0x4c9/0x5b0 [kvm]\\n   ? trace_hardirqs_off+0x4d/0xa0\\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\\nUnlike the nested VMRUN path, hoisting the svm-\u003etsc_scaling_enabled check\\ninto the if-statement is wrong as KVM needs to ensure L1\u0027s multiplier is\\nloaded in the above scenario.   Alternatively, the WARN_ON() could simply\\nbe deleted, but that would make KVM\u0027s behavior even more subtle, e.g. it\u0027s\\nnot immediately obvious why it\u0027s safe to write MSR_AMD64_TSC_RATIO when\\nchecking only tsc_ratio_msr.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.54\", \"versionStartIncluding\": \"5.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.5.4\", \"versionStartIncluding\": \"5.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6\", \"versionStartIncluding\": \"5.16\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-09-15T14:21:36.170Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2023-53208\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-01-14T17:52:56.568Z\", \"dateReserved\": \"2025-09-15T13:59:19.068Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2025-09-15T14:21:36.170Z\", \"assignerShortName\": \"Linux\"}",
      "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 observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.