{
  "cveId": "CVE-2021-23975",
  "url": "https://patchblox.com/security/cve/CVE-2021-23975",
  "summary": "CVE-2021-23975 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: Routine.",
  "title": "Firefox ESR and 1 other: The developer page about:memory has a Measure function for exploring what object types the browser has\u2026",
  "description": "The developer page about:memory has a Measure function for exploring what object types the browser has allocated and their sizes. When this function was invoked we incorrectly called the sizeof function, instead of using the API method that checks for invalid pointers. This vulnerability affects Firefox \u003C 86.",
  "published": "2021-02-25T18:15:00Z",
  "severity": "Low",
  "cvss": 6.5,
  "epss": 0.01012,
  "epssPercentile": 0.63398,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://nvd.nist.gov/vuln/detail/CVE-2021-23975",
  "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"
  }
}