Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS : Perl vulnerabilities (USN-8736-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8736-1. 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(344619);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/10");

  script_cve_id("CVE-2026-15534", "CVE-2026-19487");
  script_xref(name:"IAVA", value:"2026-A-0889");
  script_xref(name:"USN", value:"8736-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS : Perl vulnerabilities (USN-8736-1)");

  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 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS host
has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8736-1 advisory.

    It was discovered that Perl incorrectly handled certain large inputs during regular expression matching.
    An attacker could possibly use this issue to trigger out-of-bounds heap reads or writes, resulting in a
    denial of service or arbitrary code execution. (CVE-2026-15534)

    It was discovered that Perl incorrectly handled certain regular expression containing alternative matching
    branches. An attacker could

    possibly use this issue to cause incorrect regular expression matches, resulting in security restrictions
    being bypassed. (CVE-2026-19487)

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-8736-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:N/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-15534");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/08/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/10");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  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:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:Pro:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcgi-fast-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.18");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.22");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.26");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.30");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.34");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libperl5.40");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-base");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-debug");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules-5.22");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules-5.26");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules-5.30");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules-5.34");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:perl-modules-5.40");
  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 (! ('14.04' >< os_release || '16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || '26.04' >< os_release || 'Pro' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 14.04 / 16.04 / 18.04 / 20.04 / 22.04 / 26.04 / Pro', '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': '14.04', 'pkgname': 'libcgi-fast-perl', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '14.04', 'pkgname': 'libperl5.18', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '14.04', 'pkgname': 'perl', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '14.04', 'pkgname': 'perl-base', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '14.04', 'pkgname': 'perl-debug', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '14.04', 'pkgname': 'perl-modules', 'pkgver': '5.18.2-2ubuntu1.7+esm9'},
    {'osver': '16.04', 'pkgname': 'libperl5.22', 'pkgver': '5.22.1-9ubuntu0.9+esm4'},
    {'osver': '16.04', 'pkgname': 'perl', 'pkgver': '5.22.1-9ubuntu0.9+esm4'},
    {'osver': '16.04', 'pkgname': 'perl-base', 'pkgver': '5.22.1-9ubuntu0.9+esm4'},
    {'osver': '16.04', 'pkgname': 'perl-debug', 'pkgver': '5.22.1-9ubuntu0.9+esm4'},
    {'osver': '16.04', 'pkgname': 'perl-modules-5.22', 'pkgver': '5.22.1-9ubuntu0.9+esm4'},
    {'osver': '18.04', 'pkgname': 'libperl5.26', 'pkgver': '5.26.1-6ubuntu0.7+esm4'},
    {'osver': '18.04', 'pkgname': 'perl', 'pkgver': '5.26.1-6ubuntu0.7+esm4'},
    {'osver': '18.04', 'pkgname': 'perl-base', 'pkgver': '5.26.1-6ubuntu0.7+esm4'},
    {'osver': '18.04', 'pkgname': 'perl-debug', 'pkgver': '5.26.1-6ubuntu0.7+esm4'},
    {'osver': '18.04', 'pkgname': 'perl-modules-5.26', 'pkgver': '5.26.1-6ubuntu0.7+esm4'},
    {'osver': '20.04', 'pkgname': 'libperl5.30', 'pkgver': '5.30.0-9ubuntu0.5+esm4'},
    {'osver': '20.04', 'pkgname': 'perl', 'pkgver': '5.30.0-9ubuntu0.5+esm4'},
    {'osver': '20.04', 'pkgname': 'perl-base', 'pkgver': '5.30.0-9ubuntu0.5+esm4'},
    {'osver': '20.04', 'pkgname': 'perl-debug', 'pkgver': '5.30.0-9ubuntu0.5+esm4'},
    {'osver': '20.04', 'pkgname': 'perl-modules-5.30', 'pkgver': '5.30.0-9ubuntu0.5+esm4'},
    {'osver': '22.04', 'pkgname': 'libperl5.34', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': '22.04', 'pkgname': 'perl', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': '22.04', 'pkgname': 'perl-base', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': '22.04', 'pkgname': 'perl-debug', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': '22.04', 'pkgname': 'perl-modules-5.34', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': '26.04', 'pkgname': 'libperl5.40', 'pkgver': '5.40.1-7ubuntu0.2'},
    {'osver': '26.04', 'pkgname': 'perl', 'pkgver': '5.40.1-7ubuntu0.2'},
    {'osver': '26.04', 'pkgname': 'perl-base', 'pkgver': '5.40.1-7ubuntu0.2'},
    {'osver': '26.04', 'pkgname': 'perl-debug', 'pkgver': '5.40.1-7ubuntu0.2'},
    {'osver': '26.04', 'pkgname': 'perl-modules-5.40', 'pkgver': '5.40.1-7ubuntu0.2'},
    {'osver': 'Pro', 'pkgname': 'libperl5.34', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': 'Pro', 'pkgname': 'perl', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': 'Pro', 'pkgname': 'perl-base', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': 'Pro', 'pkgname': 'perl-debug', 'pkgver': '5.34.0-3ubuntu1.9'},
    {'osver': 'Pro', 'pkgname': 'perl-modules-5.34', 'pkgver': '5.34.0-3ubuntu1.9'}
];

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_WARNING,
    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, 'libcgi-fast-perl / libperl5.18 / libperl5.22 / libperl5.26 / etc');
}