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Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : ClamAV vulnerabilities (USN-8788-1)

🗓️ 25 Sep 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 1 Views

Remote DoS in ClamAV via incorrect handling of zip, PESpin, GPT, PDF, Mach-O, and XAR files.

Related
Refs
Code
ReporterTitlePublishedViews
Family
attackerkb
attackerkb
CVE-2026-20347
7 Aug 202616:42
–attackerkb
attackerkb
attackerkb
CVE-2026-20337
7 Aug 202616:41
–attackerkb
attackerkb
attackerkb
CVE-2026-20338
7 Aug 202616:41
–attackerkb
attackerkb
attackerkb
CVE-2026-20346
7 Aug 202616:42
–attackerkb
attackerkb
attackerkb
CVE-2026-20345
7 Aug 202616:42
–attackerkb
attackerkb
attackerkb
CVE-2026-20339
7 Aug 202616:42
–attackerkb
attackerkb
attackerkb
CVE-2026-20348
7 Aug 202616:42
–attackerkb
nessus
Tenable Nessus
Amazon Linux 2023 : clamav1.4, clamav1.4-data, clamav1.4-devel (ALAS2023-2026-2084)
31 Aug 202600:00
–nessus
nessus
Tenable Nessus
Amazon Linux 2023 : clamav1.5, clamav1.5-data, clamav1.5-devel (ALAS2023-2026-2116)
31 Aug 202600:00
–nessus
nessus
Tenable Nessus
Amazon Linux 2 : clamav1.4, --advisory ALAS2-2026-3894 (ALAS-2026-3894)
31 Aug 202600:00
–nessus
Rows per page
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8788-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(350303);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/25");

  script_cve_id(
    "CVE-2026-20337",
    "CVE-2026-20338",
    "CVE-2026-20339",
    "CVE-2026-20345",
    "CVE-2026-20346",
    "CVE-2026-20347",
    "CVE-2026-20348"
  );
  script_xref(name:"IAVB", value:"2026-B-0225");
  script_xref(name:"USN", value:"8788-1");

  script_name(english:"Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : ClamAV vulnerabilities (USN-8788-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple
vulnerabilities as referenced in the USN-8788-1 advisory.

    It was discovered that ClamAV incorrectly handled certain zip archive files. A remote attacker could
    possibly use this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20337,
    CVE-2026-20338)

    It was discovered that ClamAV incorrectly handled certain PESpin files. A remote attacker could possibly
    use this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20339)

    It was discovered that ClamAV incorrectly handled certain GPT files. A remote attacker could possibly use
    this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20345)

    It was discovered that ClamAV incorrectly handled certain PDF files. A remote attacker could possibly use
    this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20346)

    It was discovered that ClamAV incorrectly handled certain Mach-O files. A remote attacker could possibly
    use this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20347)

    It was discovered that ClamAV incorrectly handled certain XAR files. A remote attacker could possibly use
    this issue to cause ClamAV to crash, resulting in a denial of service. (CVE-2026-20348)

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.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/notices/USN-8788-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-20348");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/08/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/21");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/25");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav-base");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav-daemon");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav-freshclam");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav-milter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamav-testfiles");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:clamdscan");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libclamav12");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Ubuntu Local Security Checks");

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('22.04' >< os_release || '24.04' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 22.04 / 24.04 / 26.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '22.04', 'pkgname': 'clamav', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamav-base', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamav-daemon', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamav-freshclam', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamav-milter', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamav-testfiles', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'clamdscan', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '22.04', 'pkgname': 'libclamav12', 'pkgver': '1.5.4+dfsg-0ubuntu0.22.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav-base', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav-daemon', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav-freshclam', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav-milter', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamav-testfiles', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'clamdscan', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '24.04', 'pkgname': 'libclamav12', 'pkgver': '1.5.4+dfsg-0ubuntu0.24.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav-base', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav-daemon', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav-freshclam', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav-milter', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamav-testfiles', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'clamdscan', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'},
    {'osver': '26.04', 'pkgname': 'libclamav12', 'pkgver': '1.5.4+dfsg-0ubuntu0.26.04.1'}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'clamav / clamav-base / clamav-daemon / clamav-freshclam / etc');
}

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25 Sep 2026 00:00Current
5.9Medium risk
Vulners AI Score5.9
CVSS 3.17.5
EPSS0.00508
SSVC
1