The version of Firefox installed on the remote host is prior to 66.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2019-07 advisory:

 - A use-after-free vulnerability can occur when a raw pointer to a DOM element on a page is obtained using JavaScript and the element is then removed while still in use. This results in a potentially exploitable crash.(CVE-2019-9790)
 - The type inference system allows the compilation of functions that can cause type confusions between arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor function is entered through on-stack replacement (OSR).This allows for possible arbitrary reading and writing of objects during an exploitable crash. (CVE-2019-9791)
 - The IonMonkey just-in-time (JIT) compiler can leak an internal JSOPTIMIZEDOUT magic value to the running script during a bailout. This magic value can then be used by JavaScript to achieve memory corruption, which results in a potentially exploitable crash.(CVE-2019-9792)
 - A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range in circumstances where users have explicitly disabled Spectre mitigations. Note: Spectre mitigations are currently enabled for all users by default settings. (CVE-2019-9793)
 - A vulnerability was discovered where specific command line arguments are not properly discarded during Firefox invocation as a shell handler for URLs. This could be used to retrieve and execute files whose location is supplied through these command line arguments if Firefox is configured as the default URI handler for a given URI scheme in third party applications and these applications insufficiently sanitize URL data. Note: This issue only affects Windows operating systems.Other operating systems are unaffected. (CVE-2019-9794)
 - A vulnerability exists where type-confusion in the IonMonkey just-in-time (JIT) compiler could potentially be used by malicious JavaScript to trigger a potentially exploitable crash. (CVE-2019-9795)
 - A use-after-free vulnerability can occur when the SMIL animation controller incorrectly registers with the refresh driver twice when only a single registration is expected. When a registration is later freed with the removal of the animation controller element, the refresh driver incorrectly leaves a dangling pointer to the driver's observer array. (CVE-2019-9796)
 - Cross-origin images can be read in violation of the same-origin policy by exporting an image after using createImageBitmap to read the image and then rendering the resulting bitmap image within a canvas element. (CVE-2019-9797)
 - On Android systems, Firefox can load a library from APITRACELIB, which is writable by all users and applications. This could allow malicious third party applications to execute a man-in-the-middle attack if a malicious code was written to that location and loaded. Note: This issue only affects Android. Other operating systems are unaffected. (CVE-2019-9798)
 - Insufficient bounds checking of data during inter-process communication might allow a compromised content process to be able to read memory from the parent process under certain conditions. (CVE-2019-9799)
 - Firefox will accept any registered Program ID as an external protocol handler and offer to launch this local application when given a matching URL on Windows operating systems. This should only happen if the program has specifically registered itself as a URL Handler in the Windows registry. Note: This issue only affects Windows operating systems. Other operating systems are unaffected. (CVE-2019-9801)
 - If a Sandbox content process is compromised, it can initiate an FTP download which will then use a child process to render the downloaded data. The downloaded data can then be passed to the Chrome process with an arbitrary file length supplied by an attacker, bypassing sandbox protections and allow for a potential memory read of adjacent data from the privileged Chrome process, which may include sensitive data.(CVE-2019-9802)
 - The Upgrade-Insecure-Requests (UIR) specification states that if UIR is enabled through Content Security Policy (CSP), navigation to a same-origin URL must be upgraded to HTTPS. Firefox will incorrectly navigate to an HTTP URL rather than perform the security upgrade requested by the CSP in some circumstances, allowing for potential man-in-the-middle attacks on the linked resources.(CVE-2019-9803)
 - In Firefox Developer Tools it is possible that pasting the result of the 'Copy as cURL' command into a command shell on macOS will cause the execution of unintended additional bash script commands if the URL was maliciously crafted. This is the result of an issue with the native version of Bash on macOS. Note: This issue only affects macOS. Other operating systems are unaffected. (CVE-2019-9804)
 - A latent vulnerability exists in the Prio library where data may be read from uninitialized memory for some functions, leading to potential memory corruption.(CVE-2019-9805)
 - A vulnerability exists during authorization prompting for FTP transaction where successive modal prompts are displayed and cannot be immediately dismissed. This allows for a denial of service (DOS) attack.(CVE-2019-9806)
 - When arbitrary text is sent over an FTP connection and a page reload is initiated, it is possible to create a modal alert message with this text as the content. This could potentially be used for social engineering attacks. (CVE-2019-9807)
 - If the source for resources on a page is through an FTP connection, it is possible to trigger a series of modal alert messages for these resources through invalid credentials or locations. These messages cannot be immediately dismissed, allowing for a denial of service (DOS) attack. (CVE-2019-9809)
 - If WebRTC permission is requested from documents with data: or blob: URLs, the permission notifications do not properly display the originating domain. The notification states Unknown origin as the requestee, leading to user confusion about which site is asking for this permission. (CVE-2019-9808)
 - Mozilla developers and community members Dragana Damjanovic, Emilio Cobos lvarez, Henri Sivonen, Narcis Beleuzu, Julian Seward, Marcia Knous, Gary Kwong, Tyson Smith, Yaron Tausky, Ronald Crane, and Andr Bargull reported memory safety bugs present in Firefox 65. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code.(CVE-2019-9789)
 - Mozilla developers and community members Bob Clary, Chun-Min Chang, Aral Yaman, Andreea Pavel, Jonathan Kew, Gary Kwong, Alex Gaynor, Masayuki Nakano, and Anne van Kesteren reported memory safety bugs present in Firefox 65 and Firefox ESR 60.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. (CVE-2019-9788)

 Note that Nessus Network Monitor 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 66.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2019-07 advisory.

  - A latent vulnerability exists in the Prio library where data may be read from uninitialized memory for     some functions, leading to potential memory corruption. (CVE-2019-9805)

  - A use-after-free vulnerability can occur when a raw pointer to a DOM element on a page is obtained using     JavaScript and the element is then removed while still in use. This results in a potentially exploitable     crash. (CVE-2019-9790)

  - The type inference system allows the compilation of functions that can cause type confusions between     arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor     function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and     writing of objects during an exploitable crash. (CVE-2019-9791)

  - The IonMonkey just-in-time (JIT) compiler can leak an internal <code>JSOPTIMIZEDOUT</code> magic value to     the running script during a bailout. This magic value can then be used by JavaScript to achieve memory     corruption, which results in a potentially exploitable crash. (CVE-2019-9792)

  - A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if     Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary     value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range     in circumstances where users have explicitly disabled Spectre mitigations.   Note: Spectre mitigations are     currently enabled for all users by default settings. (CVE-2019-9793)

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 66.0. It is, therefore, affected by multiple vulnerabilities as referenced in the mfsa2019-07 advisory.

  - A latent vulnerability exists in the Prio library where data may be read from uninitialized memory for     some functions, leading to potential memory corruption. (CVE-2019-9805)

  - A use-after-free vulnerability can occur when a raw pointer to a DOM element on a page is obtained using     JavaScript and the element is then removed while still in use. This results in a potentially exploitable     crash. (CVE-2019-9790)

  - The type inference system allows the compilation of functions that can cause type confusions between     arbitrary objects when compiled through the IonMonkey just-in-time (JIT) compiler and when the constructor     function is entered through on-stack replacement (OSR). This allows for possible arbitrary reading and     writing of objects during an exploitable crash. (CVE-2019-9791)

  - The IonMonkey just-in-time (JIT) compiler can leak an internal <code>JSOPTIMIZEDOUT</code> magic value to     the running script during a bailout. This magic value can then be used by JavaScript to achieve memory     corruption, which results in a potentially exploitable crash. (CVE-2019-9792)

  - A mechanism was discovered that removes some bounds checking for string, array, or typed array accesses if     Spectre mitigations have been disabled. This vulnerability could allow an attacker to create an arbitrary     value in compiled JavaScript, for which the range analysis will infer a fully controlled, incorrect range     in circumstances where users have explicitly disabled Spectre mitigations.   Note: Spectre mitigations are     currently enabled for all users by default settings. (CVE-2019-9793)

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.

  - On Android systems, Firefox can load a library from APITRACE_LIB, which is writable by all users and     applications. This could allow malicious third party applications to execute a man-in-the-middle attack if     a malicious code was written to that location and loaded. *Note: This issue only affects Android. Other     operating systems are unaffected.*. This vulnerability affects Firefox < 66. (CVE-2019-9798)

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

Mozilla Foundation reports :

CVE-2019-9790: Use-after-free when removing in-use DOM elements

CVE-2019-9791: Type inference is incorrect for constructors entered through on-stack replacement with IonMonkey

CVE-2019-9792: IonMonkey leaks JS_OPTIMIZED_OUT magic value to script

CVE-2019-9793: Improper bounds checks when Spectre mitigations are disabled

CVE-2019-9794: Command line arguments not discarded during execution

CVE-2019-9795: Type-confusion in IonMonkey JIT compiler

CVE-2019-9796: Use-after-free with SMIL animation controller

CVE-2019-9797: Cross-origin theft of images with createImageBitmap

CVE-2019-9798: Library is loaded from world-writable APITRACE_LIB location

CVE-2019-9799: Information disclosure via IPC channel messages

CVE-2019-9801: Windows programs that are not 'URL Handlers' are exposed to web content

CVE-2019-9802: Chrome process information leak

CVE-2019-9803: Upgrade-Insecure-Requests incorrectly enforced for same-origin navigation

CVE-2019-9804: Code execution through 'Copy as cURL' in Firefox Developer Tools on macOS

CVE-2019-9805: Potential use of uninitialized memory in Prio

CVE-2019-9806: Denial of service through successive FTP authorization prompts

CVE-2019-9807: Text sent through FTP connection can be incorporated into alert messages

CVE-2019-9809: Denial of service through FTP modal alert error messages

CVE-2019-9808: WebRTC permissions can display incorrect origin with data: and blob: URLs

CVE-2019-9789: Memory safety bugs fixed in Firefox 66

CVE-2019-9788: Memory safety bugs fixed in Firefox 66 and Firefox ESR 60.6

ID	Name	Product	Family	Published	Updated	Severity
700487	Mozilla Firefox < 66.0 Multiple Vulnerabilities	Nessus Network Monitor	Web Clients	3/29/2019	3/29/2019	critical
122947	Mozilla Firefox < 66.0	Nessus	MacOS X Local Security Checks	3/19/2019	11/18/2025	critical
122948	Mozilla Firefox < 66.0	Nessus	Windows	3/19/2019	11/18/2025	critical
243816	Linux Distros Unpatched Vulnerability : CVE-2019-9798	Nessus	Misc.	8/5/2025	8/5/2025	high
122959	FreeBSD : mozilla -- multiple vulnerabilities (05da6b56-3e66-4306-9ea3-89fafe939726)	Nessus	FreeBSD Local Security Checks	3/20/2019	6/13/2024	critical

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