{
  "cveId": "CVE-2021-47281",
  "url": "https://patchblox.com/security/cve/CVE-2021-47281",
  "summary": "CVE-2021-47281 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47281, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  ALSA: seq: Fix race of snd_seq_timer_open()  The...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ALSA: seq: Fix race of snd_seq_timer_open()  The timer instance per queue is exclusive, and snd_seq_timer_open() should have managed the concurrent accesses.  It looks as if it\u0027s checking the already existing timer instance at the beginning, but it\u0027s not right, because there is no protection, hence any later concurrent call of snd_seq_timer_open() may override the timer instance easily.  This may result in UAF, as the leftover timer instance can keep running while the queue itself gets closed, as spotted by syzkaller recently.  For avoiding the race, add a proper check at the assignment of tmr-\u003Etimeri again, and return -EBUSY if it\u0027s been already registered.",
  "published": "2024-05-21T15:15:16Z",
  "severity": "high",
  "cvss": 7,
  "cvssVector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00239,
  "epssPercentile": 0.15044,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47281",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47281",
      "released": "2024-05-21T15:15:16Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47281",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47281",
      "released": "2024-05-21T15:15:16Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47281",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47281",
      "released": "2024-05-21T15:15:16Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}