{
  "id": "CVE-2020-6819",
  "url": "https://spydr.io/cve/CVE-2020-6819",
  "published": "2020-04-24T16:15:13.370Z",
  "modified": "2026-06-17T03:23:51.823Z",
  "score": 8.1,
  "severity": "high",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "score_source": "NVD",
  "epss": 0.03039,
  "epss_percentile": 0.87113,
  "exploited": true,
  "kev": {
    "added": "2021-11-03",
    "due": "2022-05-03",
    "action": "Apply updates per vendor instructions.",
    "ransomware": "Unknown",
    "name": "Mozilla Firefox And Thunderbird Use-After-Free Vulnerability",
    "notes": "https://nvd.nist.gov/vuln/detail/CVE-2020-6819"
  },
  "ssvc_exploitation": "active",
  "vendors": [
    "Mozilla"
  ],
  "products": [
    "Mozilla Thunderbird",
    "Mozilla Firefox",
    "Mozilla Firefox ESR"
  ],
  "cwes": [
    "CWE-362",
    "CWE-416"
  ],
  "description": "Under certain conditions, when running the nsDocShell destructor, a race condition can cause a use-after-free. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Thunderbird < 68.7.0, Firefox < 74.0.1, and Firefox ESR < 68.6.1.",
  "status": "Analyzed",
  "score_type": "Primary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 8.1,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1620818",
      "tags": [
        "Exploit",
        "Issue Tracking"
      ]
    },
    {
      "url": "https://usn.ubuntu.com/4335-1/",
      "tags": [
        "Third Party Advisory"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-11/",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2020-14/",
      "tags": [
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-6819",
      "tags": [
        "US Government Resource"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2020-6819",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}