ALSA: timer: drain a slave's callback before its master detaches it

{
  "id": "b99039a4b0334768597d5ad775f73e8aeecf6948d363a93a478f6c770062f4b8",
  "url": "https://osv.dev/vulnerability/CVE-2026-68201",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALSA: timer: drain a slave's callback before its master detaches it",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: drain a slave's callback before its master detaches it snd_timer_close_locked() drains the closing instance's own in-flight callback (IFLG_CALLBACK) before freeing it, but not its slaves'. When a master instance is closed, remove_slave_links() clears each slave's ->timer; the slave's own close then reads timer == NULL and takes the branch that skips the drain entirely (snd_timer_stop_slave() also no-ops on a NULL timer). So a slave whose callback is still running when the master is closed is freed underneath the live callback, leading to use-after-free. Drain the slaves too before remove_slave_links() severs them. snd_timer_stop() has already taken this instance off the active list, so no new slave callback can be queued. Take the slaves off the ack list so a pending one can't fire either, then wait for any that is already in flight.",
    "evidence": "osv:CVE-2026-68201",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.101",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.42",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-68201",
      "aliases": [
        "CVE-2026-68201"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/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": "37745918e0e7575bc40f38da93a99b9fa6406224"
                },
                {
                  "fixed": "cd461bcfcdf8d6b6b5365941c1d3859f8bc77aa0"
                },
                {
                  "fixed": "426c0ff1c433d6030610ad4f9375746dfe931caa"
                },
                {
                  "fixed": "2b298997786876b225cff2446e11a0fa6f602f6d"
                },
                {
                  "fixed": "bdefe1346a8e6b8dc8593406dc2617e985fcbcab"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68201.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.12.0"
                },
                {
                  "fixed": "6.12.101"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.42"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-68201.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.016309796Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2b298997786876b225cff2446e11a0fa6f602f6d",
        "https://git.kernel.org/stable/c/426c0ff1c433d6030610ad4f9375746dfe931caa",
        "https://git.kernel.org/stable/c/bdefe1346a8e6b8dc8593406dc2617e985fcbcab",
        "https://git.kernel.org/stable/c/cd461bcfcdf8d6b6b5365941c1d3859f8bc77aa0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68201.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-68201",
        "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/2026/68xxx/CVE-2026-68201.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-68201",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 511023,
  "published_at": "2026-08-10T12:00:20.28+00:00"
}