The version of Thunderbird installed on the remote Windows host is prior to 158.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-109 advisory.

  - Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 157.0.1.
    (CVE-2026-106016)

  - Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks.
    On a sufficiently large message the growth guard could fail open, or the buffer could be reallocated     smaller than required, and a subsequent memcpy would then write attacker-controlled data across adjacent     heap allocations. (CVE-2026-110247)

  - A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response     containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to     hours. (CVE-2026-110249)

  - Privilege escalation in the Application Update component. This vulnerability was fixed in Firefox 158 and     Firefox ESR 153.5. (CVE-2026-109704)

  - Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the     Networking component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5. (CVE-2026-109705)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

Mozilla Thunderbird < 158.0

critical Nessus Plugin ID 365350

Version 1.4

Version 1.3

Version 1.2

Version 1.1

Version 1.4 Oct 27, 2026, 9:59 AM CVSSv3 score source (set to "CVE-2026-109780") Plugin Feed: 202610270959
Version 1.3 Oct 26, 2026, 8:43 AM CVSS temporal metrics ("CVSSv2 temporal vector" set to "CVSS2#E:POC/RL:OF/RC:C") CVSS temporal metrics ("CVSSv3 temporal vector" set to "CVSS:3.0/E:P/RL:O/RC:C") Exploit attributes ("Exploit available" set to "True") Exploit attributes ("Exploitability ease" changed from "No known exploits are available" to "Exploits are available") Plugin Feed: 202610260843
Version 1.2 Oct 16, 2026, 7:34 PM Plugin metadata (Add IAVM Info) Plugin Feed: 202610161934
Version 1.1 Oct 13, 2026, 11:46 PM New Plugin Feed: 202610132346