Mozilla Firefox Security Advisory (MFSA2021-38) - 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("1.3.6.1.4.1.25623.1.2.1.2021.38");
  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:"2021-11-04 20:49:41 +0000 (Thu, 04 Nov 2021)");

  script_cve_id("CVE-2021-38491", "CVE-2021-38493", "CVE-2021-38494");

  script_name("Mozilla Firefox Security Advisory (MFSA2021-38) - 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:"MFSA2021-38");
  script_xref(name:"URL", value:"https://www.mozilla.org/en-US/security/advisories/mfsa2021-38/");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1551886");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1723391%2C1724101%2C1724107");
  script_xref(name:"URL", value:"https://bugzilla.mozilla.org/buglist.cgi?bug_id=1723920%2C1725638");

  script_tag(name:"summary", value:"The remote host is missing an update for Mozilla Firefox, announced via the advisory MFSA2021-38.");

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

  script_tag(name:"insight", value:"CVE-2021-38491: Mixed-Content-Blocking was unable to check opaque origins

Mixed-content checks were unable to analyze opaque origins which led to some mixed content being loaded.

CVE-2021-38493: Memory safety bugs fixed in Firefox 92, Firefox ESR 78.14 and Firefox ESR 91.1

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-2021-38494: Memory safety bugs fixed in Firefox 92

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.");

  script_tag(name:"affected", value:"Mozilla Firefox versions prior to 92.");

  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: "92")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "92", install_path: location);
  security_message(port: 0, data: report);
  exit(0);
}

exit(99);