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Linux Distros Unpatched Vulnerability : CVE-2020-26967

🗓️ 09 Aug 2025 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 1 Views

Unpatched Linux CVE-2020-26967 Firefox <83 MutationObserver misleads Screenshots Nessus patch status

Related
Refs
Code
ReporterTitlePublishedViews
Family
AlpineLinux
CVE-2020-26967
9 Dec 202000:25
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ArchLinux
[ASA-202011-12] firefox: multiple issues
17 Nov 202000:00
archlinux
Circl
CVE-2020-26967
9 Dec 202007:35
circl
CNNVD
Mozilla Firefox 安全漏洞
17 Nov 202000:00
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CNVD
Unspecified Vulnerability in Mozilla Firefox (CNVD-2021-00391)
21 Dec 202000:00
cnvd
CVE
CVE-2020-26967
9 Dec 202000:25
cve
Cvelist
CVE-2020-26967
9 Dec 202000:25
cvelist
Debian CVE
CVE-2020-26967
9 Dec 202000:25
debiancve
EUVD
EUVD-2020-19491
7 Oct 202500:30
euvd
Kaspersky
KLA12010 Multiple vulnerabilities in Mozilla Firefox
17 Nov 202000:00
kaspersky
Rows per page
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(246680);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/08/09");

  script_cve_id("CVE-2020-26967");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2020-26967");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox
    Screenshots into interacting with elements other than those that it injected into the page. This would
    lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects
    Firefox < 83. (CVE-2020-26967)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2020-26967");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-26967");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/11/17");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/08/09");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:mozjs38");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:mozjs52");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:mozjs68");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2025 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "libmozjs-52-0"},
          {"reference": "libmozjs-52-dev"},
          {"reference": "mozjs38"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "libmozjs-68-0"},
          {"reference": "libmozjs-68-dev"},
          {"reference": "mozjs52"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}

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09 Aug 2025 00:00Current
7.5High risk
Vulners AI Score7.5
CVSS 24.3
CVSS 3.16.5
EPSS0.00186
1