Skip to content
Heist/ feed
Back to feed
HighFix available

ALSA: us122l: Prevent write upgrades for read mappings

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.271, 5.15.222, 6.1.189, 6.12.111, 6.18.53, 6.6.158, 7.2.7
CVEs
CVE-2026-97931
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 01:52 UTC · Revision 1

Source evidence

ALSA: us122l: Prevent write upgrades for read mappings

core-osv · Original source

Published 25 Sept 2026, 10:22 UTC

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.

osv:CVE-2026-97931

Kernel

Fixed versions: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7

Complete source record
{
  "id": "4e44c9f43b60af55cf173920a97cc3f61860207d9660211b8f65634cbe3acb91",
  "url": "https://osv.dev/vulnerability/CVE-2026-97931",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALSA: us122l: Prevent write upgrades for read mappings",
    "summary": "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.",
    "evidence": "osv:CVE-2026-97931",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.271",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.222",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.189",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.158",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.111",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.53",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-97931",
      "aliases": [
        "CVE-2026-97931"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "030a07e441296c372f946cd4065b5d831d8dc40c"
                },
                {
                  "fixed": "cbc1f954ce67d739d41d1f0757d29850353ebb6a"
                },
                {
                  "fixed": "becb89036a1320ef0a77da2d27935ac0704345c4"
                },
                {
                  "fixed": "6a5f5a5a32c78e67701f1d0f26bc87af68895604"
                },
                {
                  "fixed": "938e8d6cee8d36f24669dfdcd3717e081eb32d64"
                },
                {
                  "fixed": "64a87950239867682cde128020e1a47088295e5c"
                },
                {
                  "fixed": "d9c537b14f4982f17b103e3a2cfeee4bee6bc026"
                },
                {
                  "fixed": "0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f"
                },
                {
                  "fixed": "71c610aeb1770302ac9c9e0b9a4ecd37f1311928"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97931.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.28"
                },
                {
                  "fixed": "5.10.271"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.222"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.189"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.158"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.111"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.53"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97931.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.528278477Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0eb9dd4774af0ac4d1fd105ef2b0a1f6cec06f2f",
        "https://git.kernel.org/stable/c/64a87950239867682cde128020e1a47088295e5c",
        "https://git.kernel.org/stable/c/6a5f5a5a32c78e67701f1d0f26bc87af68895604",
        "https://git.kernel.org/stable/c/71c610aeb1770302ac9c9e0b9a4ecd37f1311928",
        "https://git.kernel.org/stable/c/938e8d6cee8d36f24669dfdcd3717e081eb32d64",
        "https://git.kernel.org/stable/c/becb89036a1320ef0a77da2d27935ac0704345c4",
        "https://git.kernel.org/stable/c/cbc1f954ce67d739d41d1f0757d29850353ebb6a",
        "https://git.kernel.org/stable/c/d9c537b14f4982f17b103e3a2cfeee4bee6bc026",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97931.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-97931",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97931.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-97931",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509217,
  "published_at": "2026-09-25T10:22:47.382+00:00"
}