Ubuntu 26.04 LTS : curl vulnerabilities (USN-8927-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8927-1. 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(367202);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/19");

  script_cve_id(
    "CVE-2026-86409",
    "CVE-2026-86410",
    "CVE-2026-86412",
    "CVE-2026-86414",
    "CVE-2026-87862",
    "CVE-2026-87863",
    "CVE-2026-87864",
    "CVE-2026-87865",
    "CVE-2026-92386",
    "CVE-2026-92387",
    "CVE-2026-92388",
    "CVE-2026-92389",
    "CVE-2026-92390",
    "CVE-2026-92391",
    "CVE-2026-92392",
    "CVE-2026-94266",
    "CVE-2026-107928",
    "CVE-2026-107929"
  );
  script_xref(name:"USN", value:"8927-1");

  script_name(english:"Ubuntu 26.04 LTS : curl vulnerabilities (USN-8927-1)");

  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 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in
the USN-8927-1 advisory.

    It was discovered that curl, when built with GnuTLS support, had an out-of-bounds read in the WebSocket
    send path. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-107928)

    Maksim discovered that curl did not correctly include the interface binding in connection reuse decisions
    when CURLOPT_INTERFACE was used. An attacker could possibly use this issue to cause connections to go out
    from an unintended source address. (CVE-2026-107929)

    Stanislav Fort discovered that curl did not properly clear AWS SigV4 authentication state when
    CURLOPT_AWS_SIGV4 was set to NULL. An attacker could possibly use this issue to obtain sensitive
    information. (CVE-2026-86409)

    Stanislav Fort discovered that the curl command line tool did not set SSH host verification options when
    following redirects to SFTP or SCP URLs. An attacker could possibly use this issue to perform machine-in-
    the-middle attacks. (CVE-2026-86410)

    Stanislav Fort discovered that curl did not properly handle cookie jar entries that could not be reloaded.
    An attacker could possibly use this issue to cause a denial of service. (CVE-2026-86412)

    Stanislav Fort discovered that an HTTP proxy could trick libcurl into sending credentials to the proxy
    itself by responding to a CONNECT request with an unexpected authentication challenge. An attacker could
    possibly use this issue to obtain sensitive information. (CVE-2026-86414)

    Stanislav Fort discovered that curl did not correctly handle HSTS entries when an includeSubDomains parent
    entry was imported before a longer-lived child entry. An attacker could possibly use this issue to cause
    curl to use unencrypted HTTP connections. (CVE-2026-87862)

    Stanislav Fort discovered that curl did not properly handle HSTS max-age values that exceeded calendar
    time structure bounds. An attacker could possibly use this issue to cause a denial of service or data
    loss. (CVE-2026-87863)

    Stanislav Fort discovered that curl did not properly handle IMAP APPEND commands when CURLOPT_CRLF was
    enabled, allowing overflow bytes to be interpreted as pipelined commands. An authenticated attacker could
    possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-87864)

    Bobbeh Rhino discovered that libcurl, when used with libssh2 and a hashed known_hosts file, could
    misreport a host key mismatch as a missing key. An attacker could possibly use this issue to perform
    machine-in-the-middle attacks. (CVE-2026-87865)

    Joshua Rogers discovered that curl did not properly handle long cookie entries written to a Netscape
    cookie jar. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-92386)

    Joshua Rogers discovered that a malicious FTP, IMAP, POP3, or SMTP server could cause libcurl to block
    indefinitely by omitting the final control-response line. An attacker could possibly use this issue to
    cause a denial of service. (CVE-2026-92387)

    Joshua Rogers discovered that libcurl had a use-after-free vulnerability in the FTP wildcard matching
    code. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of service,
    or execute arbitrary code. (CVE-2026-92388)

    Joshua Rogers discovered that libcurl's TFTP state machine did not properly validate transfer directions,
    allowing a malicious server to force the client into transmit mode. An attacker could possibly use this
    issue to obtain sensitive information. (CVE-2026-92389)

    Joshua Rogers discovered that curl did not properly enforce its file overwrite protection when using
    --remote-header-name in certain circumstances. An attacker could possibly use this issue to overwrite
    local files. (CVE-2026-92390)

    Joshua Rogers discovered that curl had a stack overflow vulnerability when processing deeply nested MIME
    structures. An attacker could possibly use this issue to cause curl to crash, resulting in a denial of
    service. (CVE-2026-92391)

    Joshua Rogers discovered that libcurl could expose credentials in the URL returned by
    CURLINFO_EFFECTIVE_URL when credentials were retrieved from a .netrc file. An attacker could possibly use
    this issue to obtain sensitive information. (CVE-2026-94266)

    Joshua Rogers discovered that libcurl had a use-after-free vulnerability during HTTP/2 uploads when
    handling RST_STREAM responses from the server. An attacker could possibly use this issue to cause curl to
    crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-92392)

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-8927-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected curl, libcurl3t64-gnutls and / or libcurl4t64 packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/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:H/PR:N/UI:N/S:U/C:H/I:H/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-2026-92392");

  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:"2026/10/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/14");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/19");

  script_set_attribute(attribute:"plugin_type", value:"local");
  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:curl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl3t64-gnutls");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:libcurl4t64");
  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_info2.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 (! ('26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 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': '26.04', 'pkgname': 'curl', 'pkgver': '8.18.0-1ubuntu2.8'},
    {'osver': '26.04', 'pkgname': 'libcurl3t64-gnutls', 'pkgver': '8.18.0-1ubuntu2.8'},
    {'osver': '26.04', 'pkgname': 'libcurl4t64', 'pkgver': '8.18.0-1ubuntu2.8'}
];

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, 'curl / libcurl3t64-gnutls / libcurl4t64');
}