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CVE-2022-49562 (GCVE-0-2022-49562)

Vulnerability from cvelistv5 – Published: 2025-02-26 02:14 – Updated: 2026-08-05 08:55
VLAI
Title
KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < 38b888911e8dc89b89d8147cfb1d2dbe6373bf78 (git)
Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < 8089e5e1d18402fb8152d6b6815450a36fffa9b0 (git)
Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < f122dfe4476890d60b8c679128cd2259ec96a24c (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.2
Unaffected: 0 , < 5.2 (semver)
Unaffected: 5.17.13 , ≤ 5.17.* (semver)
Unaffected: 5.18.2 , ≤ 5.18.* (semver)
Unaffected: 5.19 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/mmu/paging_tmpl.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "bd53cb35a3e9adb73a834a36586e9ad80e877767",
              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "version": "5.2"
            },
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              "version": "0",
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            },
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              "version": "5.17.13",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.18.2",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.19",
              "versionType": "original_commit_for_fix"
            }
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits\n\nUse the recently introduced __try_cmpxchg_user() to update guest PTE A/D\nbits instead of mapping the PTE into kernel address space.  The VM_PFNMAP\npath is broken as it assumes that vm_pgoff is the base pfn of the mapped\nVMA range, which is conceptually wrong as vm_pgoff is the offset relative\nto the file and has nothing to do with the pfn.  The horrific hack worked\nfor the original use case (backing guest memory with /dev/mem), but leads\nto accessing \"random\" pfns for pretty much any other VM_PFNMAP case."
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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              "value": "AV:L - Exploitation requires local access to /dev/kvm and KVM ioctls (KVM_CREATE_VM/VCPU, KVM_SET_USER_MEMORY_REGION, KVM_TRANSLATE or guest page walks); it is not reachable via network packets.\nAC:L - The attacker fully controls the VM_PFNMAP backing (e.g. io_uring SQE mmap), guest page-table contents, and the ioctl/page-walk trigger, and public reproducers reliably hit the bad memremap/CMPXCHG path.\nPR:L - /dev/kvm is usable by unprivileged local users (kvm group or equivalent); no root or init-namespace admin capability is required, as confirmed by the CVE-2022-1158 disclosure.\nUI:N - The attacker triggers the bug entirely from their own process via KVM and mmap syscalls; no victim action is required.\nS:U - A host userspace KVM client corrupts the host kernel in the same privilege domain; this is local privilege escalation, not a guest-to-host escape across a VM boundary.\nC:H - The bug writes to attacker-influenced wrong physical pages (demonstrated UAF/kernel corruption), which can be leveraged for privilege escalation and thus full confidentiality compromise.\nI:H - cmpxchg_gpte() performs an out-of-bounds CMPXCHG write into incorrectly computed physical memory, enabling arbitrary kernel memory corruption and potential control-flow hijacking.\nA:H - The erroneous physical write reliably causes kernel faults/UAF crashes (as shown by KASAN in the public reproducer), yielding high availability impact."
            }
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        "dateUpdated": "2026-08-05T08:55:46.165Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
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          "url": "https://git.kernel.org/stable/c/8089e5e1d18402fb8152d6b6815450a36fffa9b0"
        },
        {
          "url": "https://git.kernel.org/stable/c/f122dfe4476890d60b8c679128cd2259ec96a24c"
        }
      ],
      "title": "KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49562",
    "datePublished": "2025-02-26T02:14:06.515Z",
    "dateReserved": "2025-02-26T02:08:31.591Z",
    "dateUpdated": "2026-08-05T08:55:46.165Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-09-16",
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      "percentile": "0.18954"
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The horrific hack worked\\nfor the original use case (backing guest memory with /dev/mem), but leads\\nto accessing \\\"random\\\" pfns for pretty much any other VM_PFNMAP case.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: x86: Use __try_cmpxchg_user() para actualizar los bits A/D de la PTE invitada Use la recientemente introducida __try_cmpxchg_user() para actualizar los bits A/D de la PTE invitada en lugar de mapear la PTE en el espacio de direcciones del kernel. La ruta VM_PFNMAP est\u00e1 rota ya que asume que vm_pgoff es la pfn base del rango VMA mapeado, lo cual es conceptualmente incorrecto ya que vm_pgoff es el desplazamiento relativo al archivo y no tiene nada que ver con la pfn. El horrible hack funcion\u00f3 para el caso de uso original (respaldar la memoria invitada con /dev/mem), pero conduce al acceso a pfn \\\"aleatorios\\\" para pr\u00e1cticamente cualquier otro caso VM_PFNMAP.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"arch/x86/kvm/mmu/paging_tmpl.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"bd53cb35a3e9adb73a834a36586e9ad80e877767\",\"lessThan\":\"38b888911e8dc89b89d8147cfb1d2dbe6373bf78\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bd53cb35a3e9adb73a834a36586e9ad80e877767\",\"lessThan\":\"8089e5e1d18402fb8152d6b6815450a36fffa9b0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bd53cb35a3e9adb73a834a36586e9ad80e877767\",\"lessThan\":\"f122dfe4476890d60b8c679128cd2259ec96a24c\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"arch/x86/kvm/mmu/paging_tmpl.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.2\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.2\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.17.13\",\"lessThanOrEqual\":\"5.17.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.18.2\",\"lessThanOrEqual\":\"5.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.19\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"NVD-CWE-noinfo\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.2\",\"versionEndExcluding\":\"5.17.13\",\"matchCriteriaId\":\"036CD419-598A-4414-8106-19AC0696AAF2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.18\",\"versionEndExcluding\":\"5.18.2\",\"matchCriteriaId\":\"9FF255A1-64F4-4E31-AF44-C92FB8773BA2\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/38b888911e8dc89b89d8147cfb1d2dbe6373bf78\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/8089e5e1d18402fb8152d6b6815450a36fffa9b0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f122dfe4476890d60b8c679128cd2259ec96a24c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:44:45+00:00",
      "cve": "CVE-2022-49562",
      "id": "CVE-2022-49562",
      "initial_release_date": "2022-01-01T00:00:00+00:00",
      "product_status:fixed": "201",
      "product_status:known_affected": "70",
      "product_status:known_not_affected": "118",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2022/cve-2022-49562.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-06T17:07:35Z",
      "cve": "CVE-2022-49562",
      "id": "CVE-2022-49562",
      "initial_release_date": "2025-02-27T03:04:58Z",
      "product_status:known_affected": "403",
      "product_status:known_not_affected": "332",
      "product_status:recommended": "250",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2022-49562",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2022-49562.json",
      "version": "48"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.