{
  "fix": "Mozilla Thunderbird (rm) 155.0",
  "url": "https://patchblox.com/security/fix/windows-app/mozilla.thunderbird.rm-155.0",
  "summary": "Mozilla Thunderbird (rm) 155.0, released September 1, 2026, fixes 31 CVEs in Mozilla Thunderbird (rm). None of them is reported as exploited. Patch Radar priority: Urgent. The latest Mozilla Thunderbird (rm) is 159.0, which also fixes every one of these CVEs.",
  "platform": "windows-app",
  "type": "app-version",
  "title": "Mozilla Thunderbird (rm) 155.0",
  "released": "2026-09-01T00:00:00Z",
  "priority": "Urgent",
  "priorityTier": 2,
  "priorityReason": "Closes CVE-2026-84637, rated Critical",
  "supported": true,
  "cveCount": 31,
  "exploitedCveCount": 0,
  "kevCveCount": 0,
  "ransomwareCveCount": 0,
  "maxEpss": 0.00626,
  "maxCvss": 9.8,
  "appliesTo": [
    {
      "product": "Mozilla Thunderbird (rm)",
      "productUrl": "https://patchblox.com/security/product/windows-app/mozilla-thunderbird-rm",
      "fixedVersion": "155.0",
      "latestVersion": "159.0",
      "supported": true
    }
  ],
  "supersededBy": {
    "product": "Mozilla Thunderbird (rm)",
    "latestVersion": "159.0",
    "productUrl": "https://patchblox.com/security/product/windows-app/mozilla-thunderbird-rm"
  },
  "cves": [
    {
      "cveId": "CVE-2026-84637",
      "url": "https://patchblox.com/security/cve/CVE-2026-84637",
      "title": "Calendar invitation attachments could launch local executables",
      "priority": "Urgent",
      "cvss": 9.8,
      "epss": 0.00626,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84134",
      "url": "https://patchblox.com/security/cve/CVE-2026-84134",
      "title": "Other issue in the Profile Backup component",
      "priority": "Urgent",
      "cvss": 9.8,
      "epss": 0.0057,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84142",
      "url": "https://patchblox.com/security/cve/CVE-2026-84142",
      "title": "Internally found bugs fixed in Thunderbird 155",
      "priority": "Urgent",
      "cvss": 9.8,
      "epss": 0.00561,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84143",
      "url": "https://patchblox.com/security/cve/CVE-2026-84143",
      "title": "Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15",
      "priority": "Urgent",
      "severity": "critical",
      "cvss": 9.8,
      "epss": 0.00378,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84639",
      "url": "https://patchblox.com/security/cve/CVE-2026-84639",
      "title": "Uninitialized memory in MIME parsing",
      "priority": "Urgent",
      "severity": "critical",
      "cvss": 9.1,
      "epss": 0.00323,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84119",
      "url": "https://patchblox.com/security/cve/CVE-2026-84119",
      "title": "Sandbox escape due to use-after-free in the DOM: Navigation component",
      "priority": "Urgent",
      "severity": "critical",
      "cvss": 9.6,
      "epss": 0.00319,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84121",
      "url": "https://patchblox.com/security/cve/CVE-2026-84121",
      "title": "Sandbox escape due to use-after-free in the DOM: Security component",
      "priority": "Urgent",
      "severity": "critical",
      "cvss": 9.6,
      "epss": 0.00319,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84130",
      "url": "https://patchblox.com/security/cve/CVE-2026-84130",
      "title": "Information disclosure in the Graphics: WebGPU component",
      "priority": "High",
      "cvss": 7.5,
      "epss": 0.00439,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84128",
      "url": "https://patchblox.com/security/cve/CVE-2026-84128",
      "title": "Privilege escalation in the WebDriver BiDi component",
      "priority": "High",
      "cvss": 8.8,
      "epss": 0.00437,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84123",
      "url": "https://patchblox.com/security/cve/CVE-2026-84123",
      "title": "Privilege escalation due to use-after-free in the Graphics: WebGPU component",
      "priority": "High",
      "cvss": 8.8,
      "epss": 0.00436,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84144",
      "url": "https://patchblox.com/security/cve/CVE-2026-84144",
      "title": "Internally found bugs fixed in Thunderbird 155 and Thunderbird ESR 153.2",
      "priority": "High",
      "cvss": 7.5,
      "epss": 0.00425,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84642",
      "url": "https://patchblox.com/security/cve/CVE-2026-84642",
      "title": "Allowed UNC hostnames for attachments interpreted as a regular expression",
      "priority": "High",
      "cvss": 7.5,
      "epss": 0.00417,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84145",
      "url": "https://patchblox.com/security/cve/CVE-2026-84145",
      "title": "Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15",
      "priority": "High",
      "severity": "high",
      "cvss": 7.5,
      "epss": 0.0037,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84141",
      "url": "https://patchblox.com/security/cve/CVE-2026-84141",
      "title": "Integer overflow in the Graphics: ImageLib component",
      "priority": "High",
      "severity": "important",
      "cvss": 9.8,
      "epss": 0.00342,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84131",
      "url": "https://patchblox.com/security/cve/CVE-2026-84131",
      "title": "Privilege escalation due to invalid pointer in the Graphics component",
      "priority": "High",
      "severity": "high",
      "cvss": 8.8,
      "epss": 0.00328,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84641",
      "url": "https://patchblox.com/security/cve/CVE-2026-84641",
      "title": "Information disclosure due to malicious IMAP server response",
      "priority": "High",
      "severity": "high",
      "cvss": 7.5,
      "epss": 0.00267,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84640",
      "url": "https://patchblox.com/security/cve/CVE-2026-84640",
      "title": "One byte overflow read in mail parser",
      "priority": "High",
      "severity": "high",
      "cvss": 7.5,
      "epss": 0.00263,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84132",
      "url": "https://patchblox.com/security/cve/CVE-2026-84132",
      "title": "Information disclosure in the Networking: HTTP component",
      "priority": "High",
      "severity": "important",
      "cvss": 7.5,
      "epss": 0.00256,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84120",
      "url": "https://patchblox.com/security/cve/CVE-2026-84120",
      "title": "Use-after-free in the Audio/Video component",
      "priority": "High",
      "severity": "medium",
      "cvss": 7.5,
      "epss": 0.00219,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84122",
      "url": "https://patchblox.com/security/cve/CVE-2026-84122",
      "title": "Use-after-free in the Audio/Video component",
      "priority": "High",
      "severity": "medium",
      "cvss": 7.5,
      "epss": 0.00214,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84129",
      "url": "https://patchblox.com/security/cve/CVE-2026-84129",
      "title": "Site isolation issue in the DOM: Navigation component",
      "priority": "High",
      "severity": "important",
      "cvss": 9.8,
      "epss": 0.00185,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84133",
      "url": "https://patchblox.com/security/cve/CVE-2026-84133",
      "title": "Site isolation issue in the DOM: Push Subscriptions component",
      "priority": "High",
      "severity": "important",
      "cvss": 9.8,
      "epss": 0.00185,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84140",
      "url": "https://patchblox.com/security/cve/CVE-2026-84140",
      "title": "Site isolation issue in the DOM: Navigation component",
      "priority": "High",
      "severity": "important",
      "cvss": 9.8,
      "epss": 0.00182,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84124",
      "url": "https://patchblox.com/security/cve/CVE-2026-84124",
      "title": "Use-after-free in the DOM: Core \u0026 HTML component",
      "priority": "High",
      "severity": "medium",
      "cvss": 8.8,
      "epss": 0.0017,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84138",
      "url": "https://patchblox.com/security/cve/CVE-2026-84138",
      "title": "Denial-of-service in the PDF Viewer component",
      "priority": "Routine",
      "cvss": 6.5,
      "epss": 0.00372,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84139",
      "url": "https://patchblox.com/security/cve/CVE-2026-84139",
      "title": "Clickjacking issue in the DOM: Events component",
      "priority": "Routine",
      "cvss": 6.1,
      "epss": 0.00337,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84126",
      "url": "https://patchblox.com/security/cve/CVE-2026-84126",
      "title": "Incorrect boundary conditions in the Layout: Grid component",
      "priority": "Routine",
      "cvss": 4.3,
      "epss": 0.00312,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84118",
      "url": "https://patchblox.com/security/cve/CVE-2026-84118",
      "title": "Use-after-free in the JavaScript: GC component",
      "priority": "Routine",
      "cvss": 5.4,
      "epss": 0.00287,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84125",
      "url": "https://patchblox.com/security/cve/CVE-2026-84125",
      "title": "Use-after-free in the DOM: Core \u0026 HTML component",
      "priority": "Routine",
      "cvss": 5.4,
      "epss": 0.00287,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84136",
      "url": "https://patchblox.com/security/cve/CVE-2026-84136",
      "title": "Other issue in the DOM: Navigation component",
      "priority": "Routine",
      "severity": "important",
      "cvss": 6.1,
      "epss": 0.00202,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    },
    {
      "cveId": "CVE-2026-84137",
      "url": "https://patchblox.com/security/cve/CVE-2026-84137",
      "title": "Spoofing issue in the DOM: Core \u0026 HTML component",
      "priority": "Routine",
      "severity": "important",
      "cvss": 4.3,
      "epss": 0.00129,
      "kev": false,
      "ransomware": false,
      "exploited": false,
      "disclosed": false
    }
  ],
  "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"
  }
}