← Back to CVE Explorer

CVE-2026-97931

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: us122l: Prevent write upgrades for read mappings The hwdep mmap callback rejects read-buffer mappings that are initially writable, but leaves VM_MAYWRITE set on mappings created with PROT_READ. A process that can open the hwdep node O_RDWR can later use mprotect() to make the mapping writable. The read allocation begins with struct usb_stream. Its read_size member is used by the fault handler to decide which pages belong to the read buffer. The read VMA intentionally remains expandable because pcm_usb_stream uses mremap() after reading that size. Changing read_size first can therefore map and access pages beyond the allocation. The same member is also consumed by usb_stream_free(), where changing it can make free_pages_exact() release pages outside the allocation. Clear VM_MAYWRITE for read-buffer mappings after rejecting an initially writable VMA. This keeps the separate output-buffer mapping writable while preventing later permission upgrades.

Severity
HIGH
CVSS score
7.0 (v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-09-25 11:17:20.387000
Last modified
2026-10-19 10:17:43.997000
View original CVE JSON 
{
  "id": "CVE-2026-97931",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-25T11:17:20.387",
  "lastModified": "2026-10-19T10:17:43.997",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: us122l: Prevent write upgrades for read mappings\n\nThe hwdep mmap callback rejects read-buffer mappings that are initially\nwritable, but leaves VM_MAYWRITE set on mappings created with PROT_READ.\nA process that can open the hwdep node O_RDWR can later use mprotect() to\nmake the mapping writable.\n\nThe read allocation begins with struct usb_stream. Its read_size member is\nused by the fault handler to decide which pages belong to the read buffer.\nThe read VMA intentionally remains expandable because pcm_usb_stream uses\nmremap() after reading that size. Changing read_size first can therefore\nmap and access pages beyond the allocation. The same member is also\nconsumed by usb_stream_free(), where changing it can make\nfree_pages_exact() release pages outside the allocation.\n\nClear VM_MAYWRITE for read-buffer mappings after rejecting an initially\nwritable VMA. This keeps the separate output-buffer mapping writable while\npreventing later permission upgrades."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "sound/usb/usx2y/us122l.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "cbc1f954ce67d739d41d1f0757d29850353ebb6a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "becb89036a1320ef0a77da2d27935ac0704345c4",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "6a5f5a5a32c78e67701f1d0f26bc87af68895604",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "938e8d6cee8d36f24669dfdcd3717e081eb32d64",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "64a87950239867682cde128020e1a47088295e5c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "d9c537b14f4982f17b103e3a2cfeee4bee6bc026",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "030a07e441296c372f946cd4065b5d831d8dc40c",
              "lessThan": "71c610aeb1770302ac9c9e0b9a4ecd37f1311928",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "sound/usb/usx2y/us122l.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2.6.28",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "2.6.28",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.271",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.222",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.189",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.158",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.111",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.53",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.7",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "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:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}