{
  "cveId": "CVE-2021-23993",
  "url": "https://patchblox.com/security/cve/CVE-2021-23993",
  "summary": "CVE-2021-23993 is fixed in 7 products on 2 platforms, first by RHSA-2021:1193, released April 14, 2021. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "Thunderbird: An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent.",
  "description": "An attacker may perform a DoS attack to prevent a user from sending encrypted email to a correspondent. If an attacker creates a crafted OpenPGP key with a subkey that has an invalid self signature, and the Thunderbird user imports the crafted key, then Thunderbird may try to use the invalid subkey, but the RNP library rejects it from being used, causing encryption to fail. This vulnerability affects Thunderbird \u003C 78.9.1.",
  "published": "2021-04-12T17:00:00Z",
  "severity": "Moderate",
  "cvss": 6.5,
  "epss": 0.00423,
  "epssPercentile": 0.36895,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://nvd.nist.gov/vuln/detail/CVE-2021-23993",
  "fixes": [
    {
      "platform": "windows-app",
      "product": "Mozilla Thunderbird (en-US)",
      "fixedVersion": "78.10.0",
      "fix": "Mozilla Thunderbird (en-US) 78.10.0",
      "url": "https://patchblox.com/security/fix/windows-app/mozilla.thunderbird-78.10.0",
      "released": "2021-04-15T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird",
      "release": "RHEL 8",
      "fixedVersion": "0:78.9.1-1.el8_3",
      "fix": "RHSA-2021:1193",
      "url": "https://patchblox.com/security/fix/linux/rhsa-2021-1193",
      "released": "2021-04-14T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "thunderbird 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-thunderbird-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "thunderbird 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-thunderbird-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird",
      "release": "ol 8",
      "fixedVersion": "0:78.9.1-1.0.1.el8_3",
      "fix": "ELSA-2021-1193",
      "url": "https://patchblox.com/security/fix/linux/elsa-2021-1193",
      "released": "2021-04-15T00:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird-gnome-support",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "thunderbird-gnome-support 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-thunderbird-gnome-support-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird-gnome-support",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "thunderbird-gnome-support 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-thunderbird-gnome-support-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird-mozsymbols",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "thunderbird-mozsymbols 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-thunderbird-mozsymbols-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "thunderbird-mozsymbols",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "thunderbird-mozsymbols 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-thunderbird-mozsymbols-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-calendar-timezones",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "xul-ext-calendar-timezones 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-xul-ext-calendar-timezones-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-calendar-timezones",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "xul-ext-calendar-timezones 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xul-ext-calendar-timezones-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-gdata-provider",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "xul-ext-gdata-provider 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-xul-ext-gdata-provider-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-gdata-provider",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "xul-ext-gdata-provider 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xul-ext-gdata-provider-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-lightning",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "fix": "xul-ext-lightning 1:78.11.0\u002Bbuild1-0ubuntu0.18.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-xul-ext-lightning-1-78.11.0-build1-0ubuntu0.18.04.2",
      "released": "2021-06-01T17:00:00Z"
    },
    {
      "platform": "linux",
      "product": "xul-ext-lightning",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "fix": "xul-ext-lightning 1:78.11.0\u002Bbuild1-0ubuntu0.20.04.2",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-xul-ext-lightning-1-78.11.0-build1-0ubuntu0.20.04.2",
      "released": "2021-06-01T17:00:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}