The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 153.1. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-77 advisory.

  - Internally found bugs present in Firefox ESR 115.38, Firefox ESR 140.13, Firefox ESR 153.0 and Firefox     153. 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-2026-74990)

  - Internally found bugs present in Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. 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-2026-74987)

  - Internally found bugs present in Firefox ESR 153.0 and Firefox 153. 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-2026-74988)

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 < 153.1

critical Nessus Plugin ID 337627

Version 1.2

Version 1.1

Version 1.2 Aug 21, 2026, 7:41 AM CVSS metrics ("CVSSv2 score" set to 10.0) CVSS metrics ("CVSSv2 vector" set to "CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C") CVSSv2 score source (changed from "CVE-2026-74990" to "CVE-2026-74944") Plugin Feed: 202608210741
Version 1.1 Aug 19, 2026, 6:09 AM New Plugin Feed: 202608190609