Mozilla Firefox Security Advisory (MFSA2021-03) - Linux

# SPDX-FileCopyrightText: 2021 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE = "cpe:/a:mozilla:firefox";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.2.1.2021.03");
  script_version("2026-07-02T06:53:57+0000");
  script_tag(name:"last_modification", value:"2026-07-02 06:53:57 +0000 (Thu, 02 Jul 2026)");
  script_tag(name:"creation_date", value:"2021-11-08 15:21:25 +0000 (Mon, 08 Nov 2021)");
  script_tag(name:"cvss_base", value:"6.8");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:M/Au:N/C:P/I:P/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-03-04 17:59:28 +0000 (Thu, 04 Mar 2021)");

  script_cve_id("CVE-2021-23953", "CVE-2021-23954", "CVE-2021-23955", "CVE-2021-23956", "CVE-2021-23958", "CVE-2021-23960", "CVE-2021-23961", "CVE-2021-23962", "CVE-2021-23963", "CVE-2021-23964", "CVE-2021-23965");

  script_name("Mozilla Firefox Security Advisory (MFSA2021-03) - Linux");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 Greenbone AG");
  script_family("General");
  script_dependencies("gb_firefox_detect_lin.nasl");
  script_mandatory_keys("mozilla/firefox/linux/detected");

  script_xref(name:"Advisory-ID", value:"MFSA2021-03");
  script_xref(name:"URL", value:"https://www.mozilla.org/en-US/security/advisories/mfsa2021-03/");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1338637");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1642747");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1662507%2C1666285%2C1673526%2C1674278%2C1674835%2C1675097%2C1675844%2C1675868%2C1677590%2C1677888%2C1680410%2C1681268%2C1682068%2C1682938%2C1683736%2C1685260%2C1685925");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1670378%2C1673555%2C1676812%2C1678582%2C1684497");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1675755");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1677194");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1677940");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1680793");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1683940");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1684020");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1684837");

  script_tag(name:"summary", value:"The remote host is missing an update for Mozilla Firefox, announced via the advisory MFSA2021-03.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable package version is present on the target host.");

  script_tag(name:"insight", value:"CVE-2021-23953: Cross-origin information leakage via redirected PDF requests

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-2021-23954: Type confusion when using logical assignment operators in JavaScript switch statements

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-2021-23955: Clickjacking across tabs through misusing requestPointerLock

The browser could have been confused into transferring a pointer lock state into another tab, which could have lead to clickjacking attacks.

CVE-2021-23956: File picker dialog could have been used to disclose a complete directory

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-2021-23958: Screen sharing permission leaked across tabs

The browser could have been confused into transferring a screen sharing state into another tab, which would leak unintended information.

CVE-2021-23960: Use-after-poison for incorrectly redeclared JavaScript variables during GC

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

CVE-2021-23961: More internal network hosts could have been probed by a malicious webpage

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-2021-23962: Use-after-poison in 'nsTreeBodyFrame::RowCountChanged'

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

CVE-2021-23963: Permission prompt inaccessible after asking for additional permissions

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-2021-23964: Memory safety bugs fixed in Firefox 85 and Firefox ESR 78.7

Mozilla developers Andrew McCreight, Tyson Smith, Jesse Schwartzentruber, Jon Coppeard, Byron Campen, Andre 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-2021-23965: Memory safety bugs fixed in Firefox 85

Mozilla developers Sebastian Hengst, Christian Holler, Tyson Smith reported memory safety bugs present in Firefox 84. Some of these bugs showed evidence ... [Please see the references for more information on the vulnerabilities]");

  script_tag(name:"affected", value:"Mozilla Firefox versions prior to 85.");

  script_tag(name:"solution", value:"The vendor has released an update. Please see the reference(s) for more information.");

  script_tag(name:"solution_type", value:"VendorFix");
  script_tag(name:"qod_type", value:"executable_version_unreliable");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if (!infos = get_app_version_and_location(cpe: CPE, exit_no_version: TRUE))
  exit(0);

version = infos["version"];
location = infos["location"];

if (version_is_less(version: version, test_version: "85")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "85", install_path: location);
  security_message(port: 0, data: report);
  exit(0);
}

exit(99);