{
  "cveId": "CVE-2021-23979",
  "url": "https://patchblox.com/security/cve/CVE-2021-23979",
  "summary": "CVE-2021-23979 is fixed in 4 products on 2 platforms, first by firefox 86.0\u002Bbuild3-0ubuntu0.18.04.1, released February 26, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "Firefox ESR and 1 other: Mozilla developers reported memory safety bugs present in Firefox 85.",
  "description": "Mozilla developers reported memory safety bugs present in Firefox 85. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox \u003C 86.",
  "published": "2021-02-26T08:15:00Z",
  "severity": "Medium",
  "cvss": 8.8,
  "epss": 0.00925,
  "epssPercentile": 0.60665,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://nvd.nist.gov/vuln/detail/CVE-2021-23979",
  "fixes": [
    {
      "platform": "windows-app",
      "product": "Mozilla Firefox ESR (en-US)",
      "fixedVersion": "91.0",
      "fix": "Mozilla Firefox ESR (en-US) 91.0",
      "url": "https://patchblox.com/security/fix/windows-app/mozilla.firefox.esr-91.0",
      "released": "2021-08-04T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "fix": "firefox 86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-86.0-build3-0ubuntu0.18.04.1",
      "released": "2021-02-26T08:15:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "fix": "firefox 86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-86.0-build3-0ubuntu0.20.04.1",
      "released": "2021-02-26T08:15:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "fix": "firefox-geckodriver 86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-geckodriver-86.0-build3-0ubuntu0.18.04.1",
      "released": "2021-02-26T08:15:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "fix": "firefox-geckodriver 86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-geckodriver-86.0-build3-0ubuntu0.20.04.1",
      "released": "2021-02-26T08:15:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "fix": "firefox-mozsymbols 86.0\u002Bbuild3-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-mozsymbols-86.0-build3-0ubuntu0.18.04.1",
      "released": "2021-02-26T08:15:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "fix": "firefox-mozsymbols 86.0\u002Bbuild3-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-mozsymbols-86.0-build3-0ubuntu0.20.04.1",
      "released": "2021-02-26T08:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}