Vulnerability-Lookup

GHSA-XPVW-H2W8-VRF9

Vulnerability from github – Published: 2025-10-22 21:31 – Updated: 2025-10-22 21:31

Details

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

5.5 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2022-49562"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-26T07:01:31Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-xpvw-h2w8-vrf9",
  "modified": "2025-10-22T21:31:16Z",
  "published": "2025-10-22T21:31:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49562"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/38b888911e8dc89b89d8147cfb1d2dbe6373bf78"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8089e5e1d18402fb8152d6b6815450a36fffa9b0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f122dfe4476890d60b8c679128cd2259ec96a24c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2025-02-26 02:14 – Updated: 2026-08-05 08:55

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

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/38b888911e8dc89b8…
https://git.kernel.org/stable/c/8089e5e1d18402fb8…
https://git.kernel.org/stable/c/f122dfe4476890d60…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < 38b888911e8dc89b89d8147cfb1d2dbe6373bf78 (git) Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < 8089e5e1d18402fb8152d6b6815450a36fffa9b0 (git) Affected: bd53cb35a3e9adb73a834a36586e9ad80e877767 , < f122dfe4476890d60b8c679128cd2259ec96a24c (git)
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)

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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": [
            {
              "lessThan": "38b888911e8dc89b89d8147cfb1d2dbe6373bf78",
              "status": "affected",
              "version": "bd53cb35a3e9adb73a834a36586e9ad80e877767",
              "versionType": "git"
            },
            {
              "lessThan": "8089e5e1d18402fb8152d6b6815450a36fffa9b0",
              "status": "affected",
              "version": "bd53cb35a3e9adb73a834a36586e9ad80e877767",
              "versionType": "git"
            },
            {
              "lessThan": "f122dfe4476890d60b8c679128cd2259ec96a24c",
              "status": "affected",
              "version": "bd53cb35a3e9adb73a834a36586e9ad80e877767",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "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": [
            {
              "status": "affected",
              "version": "5.2"
            },
            {
              "lessThan": "5.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.17.*",
              "status": "unaffected",
              "version": "5.17.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.18.*",
              "status": "unaffected",
              "version": "5.18.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.17.13",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.18.2",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.19",
                  "versionStartIncluding": "5.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "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."
        }
      ],
      "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 - 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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:55:46.165Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/38b888911e8dc89b89d8147cfb1d2dbe6373bf78"
        },
        {
          "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",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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