CVE-2022-49884 (GCVE-0-2022-49884)

Vulnerability from cvelistv5 – Published: 2025-05-01 14:10 – Updated: 2026-08-05 08:56
VLAI
Title
KVM: Initialize gfn_to_pfn_cache locks in dedicated helper
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: Initialize gfn_to_pfn_cache locks in dedicated helper Move the gfn_to_pfn_cache lock initialization to another helper and call the new helper during VM/vCPU creation. There are race conditions possible due to kvm_gfn_to_pfn_cache_init()'s ability to re-initialize the cache's locks. For example: a race between ioctl(KVM_XEN_HVM_EVTCHN_SEND) and kvm_gfn_to_pfn_cache_init() leads to a corrupted shinfo gpc lock. (thread 1) | (thread 2) | kvm_xen_set_evtchn_fast | read_lock_irqsave(&gpc->lock, ...) | | kvm_gfn_to_pfn_cache_init | rwlock_init(&gpc->lock) read_unlock_irqrestore(&gpc->lock, ...) | Rename "cache_init" and "cache_destroy" to activate+deactivate to avoid implying that the cache really is destroyed/freed. Note, there more races in the newly named kvm_gpc_activate() that will be addressed separately. [sean: call out that this is a bug fix]
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: 982ed0de4753ed6e71dbd40f82a5a066baf133ed , < 61242001d6c9c253df7645dab090842d8da08764 (git)
Affected: 982ed0de4753ed6e71dbd40f82a5a066baf133ed , < 52491a38b2c2411f3f0229dc6ad610349c704a41 (git)
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Linux Linux Affected: 5.17
Unaffected: 0 , < 5.17 (semver)
Unaffected: 6.0.8 , ≤ 6.0.* (semver)
Unaffected: 6.1 , ≤ * (original_commit_for_fix)
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          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/x86.c",
            "arch/x86/kvm/xen.c",
            "include/linux/kvm_host.h",
            "virt/kvm/pfncache.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Initialize gfn_to_pfn_cache locks in dedicated helper\n\nMove the gfn_to_pfn_cache lock initialization to another helper and\ncall the new helper during VM/vCPU creation.  There are race\nconditions possible due to kvm_gfn_to_pfn_cache_init()\u0027s\nability to re-initialize the cache\u0027s locks.\n\nFor example: a race between ioctl(KVM_XEN_HVM_EVTCHN_SEND) and\nkvm_gfn_to_pfn_cache_init() leads to a corrupted shinfo gpc lock.\n\n                (thread 1)                |           (thread 2)\n                                          |\n kvm_xen_set_evtchn_fast                  |\n  read_lock_irqsave(\u0026gpc-\u003elock, ...)      |\n                                          | kvm_gfn_to_pfn_cache_init\n                                          |  rwlock_init(\u0026gpc-\u003elock)\n  read_unlock_irqrestore(\u0026gpc-\u003elock, ...) |\n\nRename \"cache_init\" and \"cache_destroy\" to activate+deactivate to\navoid implying that the cache really is destroyed/freed.\n\nNote, there more races in the newly named kvm_gpc_activate() that will\nbe addressed separately.\n\n[sean: call out that this is a bug fix]"
        }
      ],
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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 - The bug is triggered via KVM ioctls (KVM_XEN_HVM_EVTCHN_SEND racing with KVM_XEN_HVM_SET_ATTR / gpc activate) on a VM fd from /dev/kvm, which requires local process access.\nAC:L - The attacker fully controls both sides of the race by running concurrent threads that issue EVTCHN_SEND while deactivating/reactivating the shared_info gfn_to_pfn_cache, so success does not depend on external conditions.\nPR:L - Exploitation needs only the ability to open /dev/kvm and create a VM (typically kvm-group membership); no CAP_SYS_ADMIN or real root is required along the ioctl path.\nUI:N - The attacker performs the ioctls directly against their own VM; no action by another user is required.\nS:U - The clear attack is host userspace with KVM access corrupting host kernel lock state, which is privilege escalation within the same security authority rather than a guest-to-host escape.\nC:H - Re-initializing an rwlock while it is held corrupts kernel synchronization state and can yield use-after-free / memory-corruption primitives (as related gpc races explicitly warn), enabling arbitrary confidentiality impact.\nI:H - Corrupted gpc locks and the resulting memory corruption can be leveraged for arbitrary kernel writes or control-flow hijacking, not merely a benign state inconsistency.\nA:H - Unlocking or using a re-initialized rwlock reliably causes kernel oops/BUG, hangs, or panic; the related inactive-cache race also demonstrates a direct NULL deref crash path."
            }
          ]
        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:56:33.067Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/61242001d6c9c253df7645dab090842d8da08764"
        },
        {
          "url": "https://git.kernel.org/stable/c/52491a38b2c2411f3f0229dc6ad610349c704a41"
        }
      ],
      "title": "KVM: Initialize gfn_to_pfn_cache locks in dedicated helper",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49884",
    "datePublished": "2025-05-01T14:10:30.589Z",
    "dateReserved": "2025-05-01T14:05:17.241Z",
    "dateUpdated": "2026-08-05T08:56:33.067Z",
    "state": "PUBLISHED"
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  "dataVersion": "5.2",
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      "date": "2026-10-02",
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                  "virt/kvm/pfncache.c"
                ],
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                    "versionType": "semver"
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                    "status": "unaffected",
                    "version": "6.1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Initialize gfn_to_pfn_cache locks in dedicated helper\n\nMove the gfn_to_pfn_cache lock initialization to another helper and\ncall the new helper during VM/vCPU creation.  There are race\nconditions possible due to kvm_gfn_to_pfn_cache_init()\u0027s\nability to re-initialize the cache\u0027s locks.\n\nFor example: a race between ioctl(KVM_XEN_HVM_EVTCHN_SEND) and\nkvm_gfn_to_pfn_cache_init() leads to a corrupted shinfo gpc lock.\n\n                (thread 1)                |           (thread 2)\n                                          |\n kvm_xen_set_evtchn_fast                  |\n  read_lock_irqsave(\u0026gpc-\u003elock, ...)      |\n                                          | kvm_gfn_to_pfn_cache_init\n                                          |  rwlock_init(\u0026gpc-\u003elock)\n  read_unlock_irqrestore(\u0026gpc-\u003elock, ...) |\n\nRename \"cache_init\" and \"cache_destroy\" to activate+deactivate to\navoid implying that the cache really is destroyed/freed.\n\nNote, there more races in the newly named kvm_gpc_activate() that will\nbe addressed separately.\n\n[sean: call out that this is a bug fix]"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: KVM: Inicializar bloqueos de gfn_to_pfn_cache en un asistente dedicado. Trasladar la inicializaci\u00f3n del bloqueo de gfn_to_pfn_cache a otro asistente y llamar al nuevo asistente durante la creaci\u00f3n de la m\u00e1quina virtual o la vCPU. Es posible que se produzcan condiciones de competencia debido a la capacidad de kvm_gfn_to_pfn_cache_init() de reinicializar los bloqueos de la cach\u00e9. Por ejemplo: una competencia entre ioctl(KVM_XEN_HVM_EVTCHN_SEND) y kvm_gfn_to_pfn_cache_init() provoca un bloqueo de gpc de shinfo da\u00f1ado. (hilo 1) | (hilo 2) | kvm_xen_set_evtchn_fast | read_lock_irqsave(\u0026amp;gpc-\u0026gt;lock, ...) | | kvm_gfn_to_pfn_cache_init | rwlock_init(\u0026amp;gpc-\u0026gt;lock) read_unlock_irqrestore(\u0026amp;gpc-\u0026gt;lock, ...) | Renombra \"cache_init\" y \"cache_destroy\" como activate+deactivate para evitar que la cach\u00e9 se destruya o libere. Ten en cuenta que hay m\u00e1s ejecuciones en el nuevo nombre kvm_gpc_activate() que se abordar\u00e1n por separado. [sean: se indica que se trata de una correcci\u00f3n de error]"
          }
        ],
        "id": "CVE-2022-49884",
        "lastModified": "2026-08-04T10:17:58.087",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "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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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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                "attackVector": "LOCAL",
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              "source": "nvd@nist.gov",
              "type": "Primary"
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        "vulnStatus": "Modified",
        "weaknesses": [
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            "description": [
              {
                "lang": "en",
                "value": "CWE-362"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
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    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:42:54+00:00",
      "cve": "CVE-2022-49884",
      "id": "CVE-2022-49884",
      "initial_release_date": "2022-01-01T00:00:00+00:00",
      "product_status:known_affected": "90",
      "product_status:known_not_affected": "184",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: KVM: Initialize gfn_to_pfn_cache locks in dedicated helper",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2022/cve-2022-49884.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-31T01:28:20Z",
      "cve": "CVE-2022-49884",
      "id": "CVE-2022-49884",
      "initial_release_date": "2025-05-07T02:19:14Z",
      "product_status:known_not_affected": "505",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2022-49884",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2022-49884.json",
      "version": "9"
    }
  }
}



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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

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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.
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  • 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.



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