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 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.

  - 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)

  - Mozilla developers Gabriele Svelto and Tyson Smith reported memory safety bugs present in Firefox 91 and     Firefox ESR 78.13. 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-2021-38493)

  - 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)

Note that Nessus has not tested for this issue 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.

  - 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)

  - Mozilla developers Gabriele Svelto and Tyson Smith reported memory safety bugs present in Firefox 91 and     Firefox ESR 78.13. 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-2021-38493)

  - 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)

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

ID	Name	Product	Family	Severity
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

Detections

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CVE-2021-38494

high

Tenable Plugins

high

high

high