There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - Mozilla developers reported memory safety bugs present in Firefox 84. 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. This vulnerability affects Firefox < 85. (CVE-2021-23965)

  - Using the new logical assignment operators in a JavaScript switch statement could have caused a type
    confusion, leading to a memory corruption and a potentially exploitable crash. This vulnerability affects
    Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7. (CVE-2021-23954)

  - The browser could have been confused into transferring a pointer lock state into another tab, which could
    have lead to clickjacking attacks. This vulnerability affects Firefox < 85. (CVE-2021-23955)

  - An ambiguous file picker design could have confused users who intended to select and upload a single file
    into uploading a whole directory. This was addressed by adding a new prompt. This vulnerability affects
    Firefox < 85. (CVE-2021-23956)

  - Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe
    sandbox. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This
    vulnerability affects Firefox < 85. (CVE-2021-23957)

The remote host is affected by the vulnerability described in GLSA-202102-01 (Mozilla Firefox: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Mozilla Firefox. Please       review the CVE identifiers referenced below for details.
  Impact :

    Please review the referenced CVE identifiers for details.
  Workaround :

    There is no known workaround at this time.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4717-1 advisory.

    Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially     crafted website, an attacker could potentially exploit these to cause a denial of service, obtain     sensitive information, conduct clickjacking attacks, or execute arbitrary code.

Tenable has extracted the preceding description block directly from the Ubuntu 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 Firefox installed on the remote Windows host is prior to 85.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-03 advisory.

  - Mozilla developers Sebastian Hengst, Christian Holler, Tyson Smith reported memory safety bugs present in     Firefox 84. 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-2021-23965)

  - If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-     origin information, when said information is served as chunked data. (CVE-2021-23953)

  - Using the new logical assignment operators in a JavaScript switch statement could have caused a type     confusion, leading to a memory corruption and a potentially exploitable crash. (CVE-2021-23954)

  - The browser could have been confused into transferring a pointer lock state into another tab, which could     have lead to clickjacking attacks. (CVE-2021-23955)

  - An ambiguous file picker design could have confused users who intended to select and upload a single file     into uploading a whole directory. This was addressed by adding a new prompt. (CVE-2021-23956)

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 85.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-03 advisory.

  - Mozilla developers Sebastian Hengst, Christian Holler, Tyson Smith reported memory safety bugs present in     Firefox 84. 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-2021-23965)

  - If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-     origin information, when said information is served as chunked data. (CVE-2021-23953)

  - Using the new logical assignment operators in a JavaScript switch statement could have caused a type     confusion, leading to a memory corruption and a potentially exploitable crash. (CVE-2021-23954)

  - The browser could have been confused into transferring a pointer lock state into another tab, which could     have lead to clickjacking attacks. (CVE-2021-23955)

  - An ambiguous file picker design could have confused users who intended to select and upload a single file     into uploading a whole directory. This was addressed by adding a new prompt. (CVE-2021-23956)

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

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - An ambiguous file picker design could have confused users who intended to select and upload a single file     into uploading a whole directory. This was addressed by adding a new prompt. This vulnerability affects     Firefox < 85. (CVE-2021-23956)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Published	Updated	Severity
404378	Alpine: multiple firefox packages: security update to 85.0-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	10/31/2023	7/2/2026	high
426999	Alpine: multiple librewolf packages: security update to 85.0-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	5/16/2025	7/2/2026	high
404378	Alpine: multiple firefox packages: security update to 85.0-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	10/31/2023	7/2/2026	high
426999	Alpine: multiple librewolf packages: security update to 85.0-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	5/16/2025	7/2/2026	high
145711	GLSA-202102-01 : Mozilla Firefox: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	2/1/2021	1/25/2024	high
146069	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Firefox vulnerabilities (USN-4717-1)	Nessus	Ubuntu Local Security Checks	2/3/2021	8/27/2024	high
145465	Mozilla Firefox < 85.0	Nessus	Windows	1/27/2021	11/18/2025	high
145466	Mozilla Firefox < 85.0	Nessus	MacOS X Local Security Checks	1/27/2021	11/18/2025	high
244040	Linux Distros Unpatched Vulnerability : CVE-2021-23956	Nessus	Misc.	8/6/2025	7/28/2026	medium

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