Ubuntu 18.04 LTS / 20.04 LTS : curl vulnerabilities (USN-8099-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8099-1. 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(302762);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/08");

  script_cve_id("CVE-2026-1965", "CVE-2026-3783", "CVE-2026-3784");
  script_xref(name:"USN", value:"8099-1");
  script_xref(name:"IAVA", value:"2026-A-0237-S");

  script_name(english:"Ubuntu 18.04 LTS / 20.04 LTS : curl vulnerabilities (USN-8099-1)");

  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 18.04 LTS / 20.04 LTS host has packages installed that are affected by multiple vulnerabilities as
referenced in the USN-8099-1 advisory.

    Zhicheng Chen discovered that curl could incorrectly reuse the wrong connection for Negotiate-
    authenticated HTTP or HTTPS requests. This could result in the use of credentials from a different
    connection, contrary to expectations. This issue only affected Ubuntu 20.04 LTS. (CVE-2026-1965)

    It was discovered that curl incorrectly leaked OAuth2 bearer tokens when following a redirect. This could
    result in tokens being sent to the wrong host, contrary to expectations. This issue only affected Ubuntu
    20.04 LTS. (CVE-2026-3783)

    Muhamad Arga Reksapati discovered that curl incorrectly reused existing HTTP proxy connections even if the
    request used different credentials. This could result in the use of incorrect credentials, contrary to
    expectations. (CVE-2026-3784)

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-8099-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:C/A:N");
  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:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-1965");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-3784");

  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:"2026/03/11");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/03/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/03/17");

  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:curl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl3-gnutls");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl3-nss");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl4");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl4-gnutls-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl4-nss-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl4-openssl-dev");
  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", "ubuntu_pro_sub_detect.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 (! ('18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 18.04 / 20.04', '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 ubuntu_pro_detected = get_kb_item('Host/Ubuntu/Pro/Services/esm-apps');
ubuntu_pro_detected = !empty_or_null(ubuntu_pro_detected);

var pro_caveat_needed = FALSE;

var pkgs = [
    {'osver': '18.04', 'pkgname': 'curl', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl3-gnutls', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl3-nss', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl4', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl4-gnutls-dev', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl4-nss-dev', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '18.04', 'pkgname': 'libcurl4-openssl-dev', 'pkgver': '7.58.0-2ubuntu3.24+esm8', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'curl', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl3-gnutls', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl3-nss', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl4', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl4-gnutls-dev', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl4-nss-dev', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']},
    {'osver': '20.04', 'pkgname': 'libcurl4-openssl-dev', 'pkgver': '7.68.0-1ubuntu2.25+esm3', 'ubuntu_pro': TRUE, 'cves': ['CVE-2026-1965', 'CVE-2026-3783', 'CVE-2026-3784']}
];

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

if (flag)
{
  var extra = '';
  if (pro_caveat_needed) {
    extra += 'NOTE: This vulnerability check contains fixes that apply to packages only \n';
    extra += 'available in Ubuntu ESM repositories. Access to these package security updates \n';
    extra += 'require an Ubuntu Pro subscription.\n\n';
  }
  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, 'curl / libcurl3-gnutls / libcurl3-nss / libcurl4 / etc');
}