Race condition in the Networking: DNS component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-469a21a80e advisory.

    - Updated to latest upstream (158.0)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

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 Thunderbird installed on the remote macOS or Mac OS X 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.

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.

The version of Firefox installed on the remote Windows host is prior to 158.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-106 advisory.

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 158.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2026-106 advisory.

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	Type	Severity
365511	Fedora 44 : firefox (2026-469a21a80e)	Nessus	Fedora Local Security Checks	Local	critical
365352	Mozilla Thunderbird < 158.0	Nessus	MacOS X Local Security Checks	Local	critical
365350	Mozilla Thunderbird < 158.0	Nessus	Windows	Local	critical
365314	Mozilla Firefox < 158.0	Nessus	Windows	Local	critical
365311	Mozilla Firefox < 158.0	Nessus	MacOS X Local Security Checks	Local	critical

Detections

Analytics

CVE-2026-109779

medium

Tenable Plugins

critical

critical

critical

critical

critical