Vulnerability-Lookup

GHSA-4M85-4X3P-6JMV

Vulnerability from github – Published: 2025-05-01 15:31 – Updated: 2025-11-10 21:30

Details

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)
                                      |

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

4.7 (Medium)


                  
                    CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2022-49884"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-05-01T15:16:13Z",
    "severity": "MODERATE"
  },
  "details": "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]",
  "id": "GHSA-4m85-4x3p-6jmv",
  "modified": "2025-11-10T21:30:29Z",
  "published": "2025-05-01T15:31:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49884"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52491a38b2c2411f3f0229dc6ad610349c704a41"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/61242001d6c9c253df7645dab090842d8da08764"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2025-05-01 14:10 – Updated: 2026-08-05 08:56

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

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7063 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/61242001d6c9c253d…
https://git.kernel.org/stable/c/52491a38b2c2411f3…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 982ed0de4753ed6e71dbd40f82a5a066baf133ed , < 61242001d6c9c253df7645dab090842d8da08764 (git) Affected: 982ed0de4753ed6e71dbd40f82a5a066baf133ed , < 52491a38b2c2411f3f0229dc6ad610349c704a41 (git)
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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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/x86.c",
            "arch/x86/kvm/xen.c",
            "include/linux/kvm_host.h",
            "virt/kvm/pfncache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "61242001d6c9c253df7645dab090842d8da08764",
              "status": "affected",
              "version": "982ed0de4753ed6e71dbd40f82a5a066baf133ed",
              "versionType": "git"
            },
            {
              "lessThan": "52491a38b2c2411f3f0229dc6ad610349c704a41",
              "status": "affected",
              "version": "982ed0de4753ed6e71dbd40f82a5a066baf133ed",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/x86.c",
            "arch/x86/kvm/xen.c",
            "include/linux/kvm_host.h",
            "virt/kvm/pfncache.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.0.*",
              "status": "unaffected",
              "version": "6.0.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.0.8",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1",
                  "versionStartIncluding": "5.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:56:33.067Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "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",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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