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.

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.

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 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 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.

  - 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)

  - 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.
    (CVE-2021-23957)

  - The browser could have been confused into transferring a screen sharing state into another tab, which     would leak unintended information. (CVE-2021-23958)

  - An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages     and the address bar.Note: This issue only affected Firefox for Android. Other operating systems are     unaffected. (CVE-2021-23959)

  - Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a     potentially exploitable crash. (CVE-2021-23960)

  - Further techniques that built on the slipstream research combined with a malicious webpage could have     exposed both an internal network's hosts as well as services running on the user's local machine.
    (CVE-2021-23961)

  - Incorrect use of the RowCountChanged method could have led to a user-after-poison and a     potentially exploitable crash. (CVE-2021-23962)

  - When sharing geolocation during an active WebRTC share, Firefox could have reset the webRTC sharing state     in the user interface, leading to loss of control over the currently granted permission (CVE-2021-23963)

  - Mozilla developers Andrew McCreight, Tyson Smith, Jesse Schwartzentruber, Jon Coppeard, Byron Campen,     Andr Bargull, Steve Fink, Jason Kratzer, Christian Holler, Alexis Beingessner reported memory safety bugs     present in Firefox 84 and Firefox ESR 78.6. 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-2021-23964)

  - 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)

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

  - 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)

  - 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.
    (CVE-2021-23957)

  - The browser could have been confused into transferring a screen sharing state into another tab, which     would leak unintended information. (CVE-2021-23958)

  - An XSS bug in internal error pages could have led to various spoofing attacks, including other error pages     and the address bar.Note: This issue only affected Firefox for Android. Other operating systems are     unaffected. (CVE-2021-23959)

  - Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a     potentially exploitable crash. (CVE-2021-23960)

  - Further techniques that built on the slipstream research combined with a malicious webpage could have     exposed both an internal network's hosts as well as services running on the user's local machine.
    (CVE-2021-23961)

  - Incorrect use of the RowCountChanged method could have led to a user-after-poison and a     potentially exploitable crash. (CVE-2021-23962)

  - When sharing geolocation during an active WebRTC share, Firefox could have reset the webRTC sharing state     in the user interface, leading to loss of control over the currently granted permission (CVE-2021-23963)

  - Mozilla developers Andrew McCreight, Tyson Smith, Jesse Schwartzentruber, Jon Coppeard, Byron Campen,     Andr Bargull, Steve Fink, Jason Kratzer, Christian Holler, Alexis Beingessner reported memory safety bugs     present in Firefox 84 and Firefox ESR 78.6. 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-2021-23964)

  - 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)

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
244040	Linux Distros Unpatched Vulnerability : CVE-2021-23956	Nessus	Misc.	medium
146069	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Firefox vulnerabilities (USN-4717-1)	Nessus	Ubuntu Local Security Checks	high
145711	GLSA-202102-01 : Mozilla Firefox: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
145466	Mozilla Firefox < 85.0	Nessus	MacOS X Local Security Checks	high
145465	Mozilla Firefox < 85.0	Nessus	Windows	high

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CVE-2021-23956

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