The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 115.40. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-83 advisory.

  - Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154 and     Thunderbird 154. (CVE-2026-75874)

  - Sandbox escape due to use-after-free in the DOM: Navigation component. This vulnerability was fixed in     Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2. (CVE-2026-84119)

  - Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR     115.40, Firefox ESR 140.15, and Firefox ESR 153.2. (CVE-2026-84120)

  - Sandbox escape due to use-after-free in the DOM: Security component. This vulnerability was fixed in     Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2. (CVE-2026-84121)

  - Internally found bugs present in Firefox 154, Firefox ESR 153.1, Firefox ESR 140.14 and Firefox ESR     115.39. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we     presume that with enough effort some of these could have been exploited. (CVE-2026-84145)

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 Firefox ESR < 115.40

critical Nessus Plugin ID 342165

Version 1.2

Version 1.1

Version 1.2 Sep 4, 2026, 12:58 PM Plugin metadata (Add IAVM info) Plugin Feed: 202609041258
Version 1.1 Sep 2, 2026, 12:19 AM New Plugin Feed: 202609020019