Mozilla developers reported memory safety bugs present in Firefox 91. 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 < 92.

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

  - Mozilla developers reported memory safety bugs present in Firefox 91. 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 < 92. (CVE-2021-38494)

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

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

  - Mozilla developers reported memory safety bugs present in Firefox 91. 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 < 92. (CVE-2021-38494)

  - Uninitialized memory in a canvas object could have caused an incorrect free() leading to memory corruption
    and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91,
    Firefox ESR < 78.13, and Firefox < 91. (CVE-2021-29980)

  - An issue present in lowering/register allocation could have led to obscure but deterministic register
    confusion failures in JITted code that would lead to a potentially exploitable crash. This vulnerability
    affects Firefox < 91 and Thunderbird < 91. (CVE-2021-29981)

  - Due to incorrect JIT optimization, we incorrectly interpreted data from the wrong type of object,
    resulting in the potential leak of a single bit of memory. This vulnerability affects Firefox < 91 and
    Thunderbird < 91. (CVE-2021-29982)

  - Firefox for Android could get stuck in fullscreen mode and not exit it even after normal interactions that
    should cause it to exit. *Note: This issue only affected Firefox for Android. Other operating systems are
    unaffected.*. This vulnerability affects Firefox < 91. (CVE-2021-29983)

The remote Ubuntu 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5074-1 advisory.

    Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially     crafted website, an attacker could potentially exploit these to cause a denial of service, bypass mixed     content blocking, 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 92.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-38 advisory.

  - Mozilla developers Christian Holler and Lars T Hansen reported memory safety bugs present in Firefox 91.
    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-2021-38494)

  - Firefox for Android allowed navigations through the `intent://` protocol, which could be used to cause     crashes and UI spoofs.  This bug only affects Firefox for Android. Other operating systems are unaffected.
    (CVE-2021-29993)

  - Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded.
    (CVE-2021-38491)

  - When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might     allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode.  This bug     only affects Firefox for Windows. Other operating systems are unaffected. (CVE-2021-38492)

  - If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the     path. This could lead to user confusion and spoofing attacks.  This bug only affects Firefox for Android.
    Other operating systems are unaffected. Note: Due to a clerical error this advisory was not included in     the original announcement, and was added in February 2022. (CVE-2021-4221)

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 92.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2021-38 advisory.

  - Mozilla developers Christian Holler and Lars T Hansen reported memory safety bugs present in Firefox 91.
    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-2021-38494)

  - Firefox for Android allowed navigations through the `intent://` protocol, which could be used to cause     crashes and UI spoofs.  This bug only affects Firefox for Android. Other operating systems are unaffected.
    (CVE-2021-29993)

  - Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded.
    (CVE-2021-38491)

  - When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might     allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode.  This bug     only affects Firefox for Windows. Other operating systems are unaffected. (CVE-2021-38492)

  - If a domain name contained a RTL character, it would cause the domain to be rendered to the right of the     path. This could lead to user confusion and spoofing attacks.  This bug only affects Firefox for Android.
    Other operating systems are unaffected. Note: Due to a clerical error this advisory was not included in     the original announcement, and was added in February 2022. (CVE-2021-4221)

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
246288	Linux Distros Unpatched Vulnerability : CVE-2021-38494	Nessus	Misc.	high
426480	Alpine: multiple librewolf packages: security update to 92.0.1-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
426480	Alpine: multiple librewolf packages: security update to 92.0.1-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
404384	Alpine: multiple firefox packages: security update to 92.0.1-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	high
404384	Alpine: multiple firefox packages: security update to 92.0.1-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	high
153183	Ubuntu 18.04 LTS / 20.04 LTS : Firefox vulnerabilities (USN-5074-1)	Nessus	Ubuntu Local Security Checks	high
153089	Mozilla Firefox < 92.0	Nessus	Windows	high
153088	Mozilla Firefox < 92.0	Nessus	MacOS X Local Security Checks	high

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