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CVE-2025-40038

Estado: AplazadaAlta (7.1)—

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

KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid

Skip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM must decode and emulate to skip the instruction if the CPU doesn't provide the next RIP, and getting the instruction bytes to decode requires reading guest memory. Reading guest memory through the emulator can fault, i.e. can sleep, which is disallowed since the fastpath handlers run with IRQs disabled.

Note, this is essentially a reapply of commit 5c30e8101e8d ("KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid"), but with different justification (KVM now grabs SRCU when skipping the instruction for other reasons).

Detalles técnicos trazas, registros y código del informe original
 BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:106
 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 32611, name: qemu
 preempt_count: 1, expected: 0
 INFO: lockdep is turned off.
 irq event stamp: 30580
 hardirqs last  enabled at (30579): [<ffffffffc08b2527>] vcpu_run+0x1787/0x1db0 [kvm]
 hardirqs last disabled at (30580): [<ffffffffb4f62e32>] __schedule+0x1e2/0xed0
 softirqs last  enabled at (30570): [<ffffffffb4247a64>] fpu_swap_kvm_fpstate+0x44/0x210
 softirqs last disabled at (30568): [<ffffffffb4247a64>] fpu_swap_kvm_fpstate+0x44/0x210
 CPU: 298 UID: 0 PID: 32611 Comm: qemu Tainted: G     U              6.16.0-smp--e6c618b51cfe-sleep #782 NONE
 Tainted: [U]=USER
 Hardware name: Google Astoria-Turin/astoria, BIOS 0.20241223.2-0 01/17/2025
 Call Trace:
  <TASK>
  dump_stack_lvl+0x7d/0xb0
  __might_resched+0x271/0x290
  __might_fault+0x28/0x80
  kvm_vcpu_read_guest_page+0x8d/0xc0 [kvm]
  kvm_fetch_guest_virt+0x92/0xc0 [kvm]
  __do_insn_fetch_bytes+0xf3/0x1e0 [kvm]
  x86_decode_insn+0xd1/0x1010 [kvm]
  x86_emulate_instruction+0x105/0x810 [kvm]
  __svm_skip_emulated_instruction+0xc4/0x140 [kvm_amd]
  handle_fastpath_invd+0xc4/0x1a0 [kvm]
  vcpu_run+0x11a1/0x1db0 [kvm]
  kvm_arch_vcpu_ioctl_run+0x5cc/0x730 [kvm]
  kvm_vcpu_ioctl+0x578/0x6a0 [kvm]
  __se_sys_ioctl+0x6d/0xb0
  do_syscall_64+0x8a/0x2c0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
 RIP: 0033:0x7f479d57a94b
  </TASK>

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local (AV:L) sin interacción que causa DoS al provocar sleep() con IRQs deshabilitados en ruta rápida de KVM/SVM; disponibilidad (A:H) comprometida mediante condición de carrera en fastpath handlers.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2025-40038",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 7.1,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 4,
        "exploitabilityScore": 2.5
      }
    ]
  },
  "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": "b439eb8ab578557263815ba8581d02c1b730e348",
              "lessThan": "cd3efb93677c4b0cf76348882fb429165fee33fd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b439eb8ab578557263815ba8581d02c1b730e348",
              "lessThan": "f994e9c790ce97d3cf01af4d0a1b9add0c955aee",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b439eb8ab578557263815ba8581d02c1b730e348",
              "lessThan": "da2a3c231f7f2a5ac146d972b8c1d7d84aff6d70",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b439eb8ab578557263815ba8581d02c1b730e348",
              "lessThan": "0910dd7c9ad45a2605c45fd2bf3d1bcac087687c",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/svm.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.5"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.5",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.6.113",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.53",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.17.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.17.*"
            },
            {
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/svm.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-10-28T12:15:37.733",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0910dd7c9ad45a2605c45fd2bf3d1bcac087687c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cd3efb93677c4b0cf76348882fb429165fee33fd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/da2a3c231f7f2a5ac146d972b8c1d7d84aff6d70",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f994e9c790ce97d3cf01af4d0a1b9add0c955aee",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid\n\nSkip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP\nisn't valid, e.g. because KVM is running with nrips=false.  SVM must\ndecode and emulate to skip the instruction if the CPU doesn't provide the\nnext RIP, and getting the instruction bytes to decode requires reading\nguest memory.  Reading guest memory through the emulator can fault, i.e.\ncan sleep, which is disallowed since the fastpath handlers run with IRQs\ndisabled.\n\n BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:106\n in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 32611, name: qemu\n preempt_count: 1, expected: 0\n INFO: lockdep is turned off.\n irq event stamp: 30580\n hardirqs last  enabled at (30579): [<ffffffffc08b2527>] vcpu_run+0x1787/0x1db0 [kvm]\n hardirqs last disabled at (30580): [<ffffffffb4f62e32>] __schedule+0x1e2/0xed0\n softirqs last  enabled at (30570): [<ffffffffb4247a64>] fpu_swap_kvm_fpstate+0x44/0x210\n softirqs last disabled at (30568): [<ffffffffb4247a64>] fpu_swap_kvm_fpstate+0x44/0x210\n CPU: 298 UID: 0 PID: 32611 Comm: qemu Tainted: G     U              6.16.0-smp--e6c618b51cfe-sleep #782 NONE\n Tainted: [U]=USER\n Hardware name: Google Astoria-Turin/astoria, BIOS 0.20241223.2-0 01/17/2025\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0x7d/0xb0\n  __might_resched+0x271/0x290\n  __might_fault+0x28/0x80\n  kvm_vcpu_read_guest_page+0x8d/0xc0 [kvm]\n  kvm_fetch_guest_virt+0x92/0xc0 [kvm]\n  __do_insn_fetch_bytes+0xf3/0x1e0 [kvm]\n  x86_decode_insn+0xd1/0x1010 [kvm]\n  x86_emulate_instruction+0x105/0x810 [kvm]\n  __svm_skip_emulated_instruction+0xc4/0x140 [kvm_amd]\n  handle_fastpath_invd+0xc4/0x1a0 [kvm]\n  vcpu_run+0x11a1/0x1db0 [kvm]\n  kvm_arch_vcpu_ioctl_run+0x5cc/0x730 [kvm]\n  kvm_vcpu_ioctl+0x578/0x6a0 [kvm]\n  __se_sys_ioctl+0x6d/0xb0\n  do_syscall_64+0x8a/0x2c0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n RIP: 0033:0x7f479d57a94b\n  </TASK>\n\nNote, this is essentially a reapply of commit 5c30e8101e8d (\"KVM: SVM:\nSkip WRMSR fastpath on VM-Exit if next RIP isn't valid\"), but with\ndifferent justification (KVM now grabs SRCU when skipping the instruction\nfor other reasons)."
    }
  ],
  "lastModified": "2026-07-30T06:24:07.030",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}