CVE-2021-47062

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This fixes a possible null-pointer dereference as\ncreated_vcpus does not guarantee a vCPU exists, since it is updated at\nthe very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the\nbulk of vCPU creation to run in parallel, while still correctly\nrestricting the max number of max vCPUs."}, {"lang": "es", "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: KVM: SVM: use online_vcpus, no creado_vcpus, para iterar sobre vCPU. Use el asistente kvm_for_each_vcpu() para iterar sobre vCPU al cifrar VMSA para SEV, que efectivamente cambia para usar online_vcpus en lugar de creado_vcpus. Esto corrige una posible desreferencia de puntero nulo ya que create_vcpus no garantiza que exista una vCPU, ya que se actualiza al comienzo de KVM_CREATE_VCPU. create_vcpus existe para permitir que la mayor parte de la creaci\u00f3n de vCPU se ejecute en paralelo, al mismo tiempo que restringe correctamente la cantidad m\u00e1xima de vCPU m\u00e1ximas."}], "id": "CVE-2021-47062", "lastModified": "2026-06-17T04:16:21.307", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2021-47062", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2024-03-05T22:14:24.335971Z", "version": "2.0.3"}}]}, "published": "2024-02-29T23:15:07.843", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/ba7bf5d6336aa9c0d977b161bfa420c56d46ee40"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/bd0cced2ae93195668f983d443f7f17e8efd24d2"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c36b16d29f3af5f32fc1b2a3401bf48f71cabee1"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: KVM: SVM: null pointer in online_vcpus, not created_vcpus, to iterate over vCPUs", "id": "2267171", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2267171"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nKVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs\nUse the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting\nVMSAs for SEV, which effectively switches to use online_vcpus instead of\ncreated_vcpus. This fixes a possible null-pointer dereference as\ncreated_vcpus does not guarantee a vCPU exists, since it is updated at\nthe very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the\nbulk of vCPU creation to run in parallel, while still correctly\nrestricting the max number of max vCPUs.", "A flaw was found in the Linux kernel's Kernel-based virtual machine (KVM) subsystem for AMD's Secure virtual machine (SVM). The issue occurs when using the created_vcpus list to iterate over vCPUs instead of the online_vcpus list, leading to a possible NULL pointer dereference. This vulnerability impacts the encryption of Virtual Machine Save Areas (VMSAs) for Secure Encrypted Virtualization (SEV)."], "name": "CVE-2021-47062", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2024-02-29T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-47062\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-47062\nhttps://lore.kernel.org/linux-cve-announce/2024022953-CVE-2021-47062-ed39@gregkh/T/#u"], "threat_severity": "Moderate"}

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