Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : SRT vulnerabilities (USN-8764-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8764-1. 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(346232);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/16");

  script_cve_id("CVE-2026-55868", "CVE-2026-55869");
  script_xref(name:"USN", value:"8764-1");

  script_name(english:"Ubuntu 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : SRT vulnerabilities (USN-8764-1)");

  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 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by
multiple vulnerabilities as referenced in the USN-8764-1 advisory.

    It was discovered that SRT did not authenticate certain encryption control messages. A remote attacker
    could possibly use this issue to downgrade an encrypted connection and inject arbitrary content or
    interrupt a media stream. (CVE-2026-55868)

    It was discovered that SRT did not properly validate certain control packets during connection setup and
    key refresh operations. A remote attacker could possibly use this issue to cause SRT to crash, resulting
    in a denial of service. (CVE-2026-55869)

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-8764-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  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:N/S:U/C:H/I:N/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-2026-55869");

  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:"2026/07/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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: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:libsrt1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsrt1.4-gnutls");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsrt1.4-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsrt1.5-gnutls");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libsrt1.5-openssl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:srt-tools");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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 (! ('20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 20.04 / 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': '20.04', 'pkgname': 'libsrt1', 'pkgver': '1.4.0-1ubuntu0.1~esm1'},
    {'osver': '20.04', 'pkgname': 'srt-tools', 'pkgver': '1.4.0-1ubuntu0.1~esm1'},
    {'osver': '22.04', 'pkgname': 'libsrt1.4-gnutls', 'pkgver': '1.4.4-4ubuntu0.1~esm1'},
    {'osver': '22.04', 'pkgname': 'libsrt1.4-openssl', 'pkgver': '1.4.4-4ubuntu0.1~esm1'},
    {'osver': '22.04', 'pkgname': 'srt-tools', 'pkgver': '1.4.4-4ubuntu0.1~esm1'},
    {'osver': '24.04', 'pkgname': 'libsrt1.5-gnutls', 'pkgver': '1.5.3-1ubuntu0.1~esm1'},
    {'osver': '24.04', 'pkgname': 'libsrt1.5-openssl', 'pkgver': '1.5.3-1ubuntu0.1~esm1'},
    {'osver': '24.04', 'pkgname': 'srt-tools', 'pkgver': '1.5.3-1ubuntu0.1~esm1'},
    {'osver': '26.04', 'pkgname': 'libsrt1.5-gnutls', 'pkgver': '1.5.4-3ubuntu0.1~esm1'},
    {'osver': '26.04', 'pkgname': 'libsrt1.5-openssl', 'pkgver': '1.5.4-3ubuntu0.1~esm1'},
    {'osver': '26.04', 'pkgname': 'srt-tools', 'pkgver': '1.5.4-3ubuntu0.1~esm1'}
];

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, 'libsrt1 / libsrt1.4-gnutls / libsrt1.4-openssl / libsrt1.5-gnutls / etc');
}