Spoofing issue in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, and Firefox ESR 140.10.

The version of Firefox installed on the remote Windows host is prior to 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-30 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of     these could have been exploited to run arbitrary code. (CVE-2026-6786)

  - Memory safety bugs present in Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of     memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. (CVE-2026-6784)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

The version of Firefox ESR installed on the remote Windows host is prior to 115.35. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-31 advisory.

  - Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox     ESR 140.8, Thunderbird 148, and Thunderbird 140.8. (CVE-2026-2781)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 140.10. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-32 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of     these could have been exploited to run arbitrary code. (CVE-2026-6786)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

The version of Firefox ESR installed on the remote macOS or Mac OS X host is prior to 115.35. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-31 advisory.

  - Integer overflow in the Libraries component in NSS. This vulnerability was fixed in Firefox 148, Firefox     ESR 140.8, Thunderbird 148, and Thunderbird 140.8. (CVE-2026-2781)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

The version of Firefox installed on the remote macOS or Mac OS X host is prior to 150.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-30 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of     these could have been exploited to run arbitrary code. (CVE-2026-6786)

  - Memory safety bugs present in Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of     memory corruption and we presume that with enough effort some of these could have been exploited to run     arbitrary code. (CVE-2026-6784)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

The version of Firefox ESR installed on the remote Windows host is prior to 140.10. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-32 advisory.

  - Memory safety bugs present in Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149 and Thunderbird 149.
    Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of     these could have been exploited to run arbitrary code. (CVE-2026-6786)

  - Memory safety bugs present in Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird ESR 140.9, Firefox 149     and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with     enough effort some of these could have been exploited to run arbitrary code. (CVE-2026-6785)

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

ID	Name	Product	Family	Severity
307899	Mozilla Firefox < 150.0	Nessus	Windows	critical
307898	Mozilla Firefox ESR < 115.35	Nessus	Windows	critical
307897	Mozilla Firefox ESR < 140.10	Nessus	MacOS X Local Security Checks	critical
307896	Mozilla Firefox ESR < 115.35	Nessus	MacOS X Local Security Checks	critical
307895	Mozilla Firefox < 150.0	Nessus	MacOS X Local Security Checks	critical
307894	Mozilla Firefox ESR < 140.10	Nessus	Windows	critical

Detections

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CVE-2026-6762

critical

Tenable Plugins

critical

critical

critical

critical

critical

critical