The version of Thunderbird installed on the remote macOS or Mac OS X host is prior to 140.9. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-24 advisory.

  - Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 149, Firefox ESR <     140.9, Thunderbird < 149, and Thunderbird < 140.9. (CVE-2026-4717)

  - Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability affects     Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9. (CVE-2026-4688)

  - Spoofing issue in Thunderbird. This vulnerability affects Thunderbird < 149 and Thunderbird < 140.9.
    (CVE-2026-3889)

  - A malicious mail server could send malformed strings with negative lengths, causing the parser to read     memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker     could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data.
    (CVE-2026-4371)

  - Race condition, use-after-free in the Graphics: WebRender component. This vulnerability affects Firefox <     149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
    (CVE-2026-4684)

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 < 140.9

critical Nessus Plugin ID 303505

Version 1.1