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CVE-2022-50425

Estado: AnalizadaMedia (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

x86/fpu: Fix copy_xstate_to_uabi() to copy init states correctly

When an extended state component is not present in fpstate, but in init state, the function copies from init_fpstate via copy_feature().

But, dynamic states are not present in init_fpstate because of all-zeros init states. Then retrieving them from init_fpstate will explode like this:

Adjust the 'mask' to zero out the userspace buffer for the features that are not available both from fpstate and from init_fpstate.

The dynamic features depend on the compacted XSAVE format. Ensure it is enabled before reading XCOMP_BV in init_fpstate.

Detalles técnicos trazas, registros y código del informe original
 BUG: kernel NULL pointer dereference, address: 0000000000000000
 ...
 RIP: 0010:memcpy_erms+0x6/0x10
  ? __copy_xstate_to_uabi_buf+0x381/0x870
  fpu_copy_guest_fpstate_to_uabi+0x28/0x80
  kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm]
  ? __this_cpu_preempt_check+0x13/0x20
  ? vmx_vcpu_put+0x2e/0x260 [kvm_intel]
  kvm_vcpu_ioctl+0xea/0x6b0 [kvm]
  ? kvm_vcpu_ioctl+0xea/0x6b0 [kvm]
  ? __fget_light+0xd4/0x130
  __x64_sys_ioctl+0xe3/0x910
  ? debug_smp_processor_id+0x17/0x20
  ? fpregs_assert_state_consistent+0x27/0x50
  do_syscall_64+0x3f/0x90
  entry_SYSCALL_64_after_hwframe+0x63/0xcd

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2022-50425",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "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"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2308ee57d93d896618dd65c996429c9d3e469fe0",
              "lessThan": "6ff29642fd28965a8f8d6d326ac91bf6075f3113",
              "versionType": "git"
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            {
              "status": "affected",
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              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/x86/kernel/fpu/xstate.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": "6.0.7",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/x86/kernel/fpu/xstate.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-01T12:15:33.987",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/471f0aa7fa64e23766a1473b32d9ec3f0718895a",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6ff29642fd28965a8f8d6d326ac91bf6075f3113",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/fpu: Fix copy_xstate_to_uabi() to copy init states correctly\n\nWhen an extended state component is not present in fpstate, but in init\nstate, the function copies from init_fpstate via copy_feature().\n\nBut, dynamic states are not present in init_fpstate because of all-zeros\ninit states. Then retrieving them from init_fpstate will explode like this:\n\n BUG: kernel NULL pointer dereference, address: 0000000000000000\n ...\n RIP: 0010:memcpy_erms+0x6/0x10\n  ? __copy_xstate_to_uabi_buf+0x381/0x870\n  fpu_copy_guest_fpstate_to_uabi+0x28/0x80\n  kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm]\n  ? __this_cpu_preempt_check+0x13/0x20\n  ? vmx_vcpu_put+0x2e/0x260 [kvm_intel]\n  kvm_vcpu_ioctl+0xea/0x6b0 [kvm]\n  ? kvm_vcpu_ioctl+0xea/0x6b0 [kvm]\n  ? __fget_light+0xd4/0x130\n  __x64_sys_ioctl+0xe3/0x910\n  ? debug_smp_processor_id+0x17/0x20\n  ? fpregs_assert_state_consistent+0x27/0x50\n  do_syscall_64+0x3f/0x90\n  entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nAdjust the 'mask' to zero out the userspace buffer for the features that\nare not available both from fpstate and from init_fpstate.\n\nThe dynamic features depend on the compacted XSAVE format. Ensure it is\nenabled before reading XCOMP_BV in init_fpstate."
    }
  ],
  "lastModified": "2026-06-17T05:23:31.773",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "65D387F0-209C-4EAD-98BA-C4B430A840C9",
              "versionEndExcluding": "6.0.7",
              "versionStartIncluding": "5.16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E7E331DA-1FB0-4DEC-91AC-7DA69D461C11"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}