{
  "cveId": "CVE-2021-29966",
  "url": "https://patchblox.com/security/cve/CVE-2021-29966",
  "summary": "CVE-2021-29966 is fixed in 4 products on 2 platforms, first by firefox 89.0\u002Bbuild2-0ubuntu0.18.04.2, released June 1, 2021. It is not reported as exploited. Patch Radar priority: High.",
  "title": "Mozilla Firefox ESR: Mozilla developers reported memory safety bugs present in Firefox 88.",
  "description": "Mozilla developers reported memory safety bugs present in Firefox 88. 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 89.",
  "published": "2021-06-01T17:00:00Z",
  "severity": "Medium",
  "cvss": 8.8,
  "epss": 0.01022,
  "epssPercentile": 0.63668,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://nvd.nist.gov/vuln/detail/CVE-2021-29966",
  "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": "89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "fix": "firefox 89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-89.0-build2-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "fix": "firefox 89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-89.0-build2-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "fix": "firefox-geckodriver 89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-geckodriver-89.0-build2-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "fix": "firefox-geckodriver 89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-geckodriver-89.0-build2-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "fix": "firefox-mozsymbols 89.0\u002Bbuild2-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-mozsymbols-89.0-build2-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "fix": "firefox-mozsymbols 89.0\u002Bbuild2-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-mozsymbols-89.0-build2-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}