{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-47281",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47281",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2024-05-21T14:20:07.499Z",
    "updatedAt": "2026-08-05T08:47:03.896Z",
    "importedAt": "2026-10-24T01:56:36.661Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "ALSA: seq: Fix race of snd_seq_timer_open()",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Fix race of snd_seq_timer_open()\n\nThe timer instance per queue is exclusive, and snd_seq_timer_open()\nshould have managed the concurrent accesses.  It looks as if it's\nchecking the already existing timer instance at the beginning, but\nit's not right, because there is no protection, hence any later\nconcurrent call of snd_seq_timer_open() may override the timer\ninstance easily.  This may result in UAF, as the leftover timer\ninstance can keep running while the queue itself gets closed, as\nspotted by syzkaller recently.\n\nFor avoiding the race, add a proper check at the assignment of\ntmr->timeri again, and return -EBUSY if it's been already registered.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "status": "affected",
              "versionType": "git",
              "lessThan": "bd7d88b0874f82f7b29d1a53e574cedaf23166ba"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "status": "affected",
              "versionType": "git",
              "lessThan": "536a7646c00a0f14fee49e5e313109e5da2f6031"
            },
            {
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "status": "affected",
              "versionType": "git",
              "lessThan": "83e197a8414c0ba545e7e3916ce05f836f349273"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "2.6.12",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "2.6.12"
            },
            {
              "version": "5.10.44",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.12.11",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "version": "5.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}