{
  "cveId": "CVE-2021-43540",
  "url": "https://patchblox.com/security/cve/CVE-2021-43540",
  "summary": "CVE-2021-43540 is fixed in 4 products on 2 platforms, first by firefox 95.0\u002Bbuild1-0ubuntu0.18.04.1, released December 7, 2021. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Mozilla Firefox ESR and 1 other: WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party\u2026",
  "description": "WebExtensions with the correct permissions were able to create and install ServiceWorkers for third-party websites that would not have been uninstalled with the extension. This vulnerability affects Firefox \u003C 95.",
  "published": "2021-12-07T16:00:00Z",
  "severity": "Medium",
  "cvss": 6.5,
  "epss": 0.0089,
  "epssPercentile": 0.59597,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://nvd.nist.gov/vuln/detail/CVE-2021-43540",
  "fixes": [
    {
      "platform": "windows-app",
      "product": "Mozilla Firefox ESR (en-US)",
      "fixedVersion": "102.0",
      "fix": "Mozilla Firefox ESR (en-US) 102.0",
      "url": "https://patchblox.com/security/fix/windows-app/mozilla.firefox.esr-102.0",
      "released": "2022-06-23T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "fix": "firefox 95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-95.0-build1-0ubuntu0.18.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "fix": "firefox 95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-95.0-build1-0ubuntu0.20.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu1",
      "fix": "firefox 95.0\u002Bbuild1-0ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-firefox-95.0-build1-0ubuntu1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "fix": "firefox-geckodriver 95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-geckodriver-95.0-build1-0ubuntu0.18.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "fix": "firefox-geckodriver 95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-geckodriver-95.0-build1-0ubuntu0.20.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-geckodriver",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu1",
      "fix": "firefox-geckodriver 95.0\u002Bbuild1-0ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-firefox-geckodriver-95.0-build1-0ubuntu1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "fix": "firefox-mozsymbols 95.0\u002Bbuild1-0ubuntu0.18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-firefox-mozsymbols-95.0-build1-0ubuntu0.18.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "fix": "firefox-mozsymbols 95.0\u002Bbuild1-0ubuntu0.20.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-firefox-mozsymbols-95.0-build1-0ubuntu0.20.04.1",
      "released": "2021-12-07T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "firefox-mozsymbols",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "95.0\u002Bbuild1-0ubuntu1",
      "fix": "firefox-mozsymbols 95.0\u002Bbuild1-0ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-firefox-mozsymbols-95.0-build1-0ubuntu1",
      "released": "2021-12-07T16:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}