ghsa-xpvw-h2w8-vrf9
Vulnerability from github
Published
2025-10-22 21:31
Modified
2025-10-22 21:31
Severity ?
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.

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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"
    }
  ]
}


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