Linux Distros Unpatched Vulnerability : CVE-2026-123746

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(377463);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/07");

  script_cve_id("CVE-2026-123746");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-123746");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - The Symfony Security HTTP component AuthenticatorManager::authenticateUser() does not run the firewall
    user checker's checkPostAuth() method when a user is authenticated programmatically, allowing an account
    rejected by a custom user checker, such as an expired account, to be authenticated in Symfony versions
    prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
    AuthenticatorManager::authenticateUser() is used by UserAuthenticatorInterface::authenticateUser() and by
    the SecurityBundle's Security::login() to authenticate a user programmatically, but it does not dispatch
    the security.authentication.success event, on which checkPostAuth() runs. The fix for CVE-2024-50341 made
    Security::login() call checkPreAuth(), but checkPostAuth() was still skipped. As a result, an account
    rejected by a custom user checker in checkPostAuth() is refused by form login and the other authenticators
    of the firewall, but can still be authenticated programmatically. Applications are affected when they use
    a custom user checker that rejects users in checkPostAuth() and authenticate users programmatically, for
    example after a password reset or an e-mail verification link. A user whose account is rejected can then
    obtain an authenticated session through that flow. The default user checker does nothing in
    checkPostAuth(), so the default configuration is not affected. The fix makes
    AuthenticatorManager::authenticateUser() dispatch the security.authentication.success event once the token
    is created and before it is stored, as authentications through the firewall do, so that checkPostAuth()
    runs and can reject the user. (CVE-2026-123746)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-123746");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-123746");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/11/06");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/11/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:symfony");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "php-symfony"},
          {"reference": "php-symfony-asset"},
          {"reference": "php-symfony-browser-kit"},
          {"reference": "php-symfony-cache"},
          {"reference": "php-symfony-config"},
          {"reference": "php-symfony-console"},
          {"reference": "php-symfony-css-selector"},
          {"reference": "php-symfony-dependency-injection"},
          {"reference": "php-symfony-dom-crawler"},
          {"reference": "php-symfony-dotenv"},
          {"reference": "php-symfony-error-handler"},
          {"reference": "php-symfony-event-dispatcher"},
          {"reference": "php-symfony-expression-language"},
          {"reference": "php-symfony-filesystem"},
          {"reference": "php-symfony-finder"},
          {"reference": "php-symfony-form"},
          {"reference": "php-symfony-http-client"},
          {"reference": "php-symfony-http-foundation"},
          {"reference": "php-symfony-http-kernel"},
          {"reference": "php-symfony-inflector"},
          {"reference": "php-symfony-intl"},
          {"reference": "php-symfony-ldap"},
          {"reference": "php-symfony-lock"},
          {"reference": "php-symfony-mailer"},
          {"reference": "php-symfony-messenger"},
          {"reference": "php-symfony-mime"},
          {"reference": "php-symfony-notifier"},
          {"reference": "php-symfony-options-resolver"},
          {"reference": "php-symfony-password-hasher"},
          {"reference": "php-symfony-process"},
          {"reference": "php-symfony-property-access"},
          {"reference": "php-symfony-property-info"},
          {"reference": "php-symfony-rate-limiter"},
          {"reference": "php-symfony-routing"},
          {"reference": "php-symfony-runtime"},
          {"reference": "php-symfony-security-core"},
          {"reference": "php-symfony-security-csrf"},
          {"reference": "php-symfony-security-guard"},
          {"reference": "php-symfony-security-http"},
          {"reference": "php-symfony-semaphore"},
          {"reference": "php-symfony-serializer"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "php-symfony"},
          {"reference": "php-symfony-asset"},
          {"reference": "php-symfony-asset-mapper"},
          {"reference": "php-symfony-browser-kit"},
          {"reference": "php-symfony-cache"},
          {"reference": "php-symfony-clock"},
          {"reference": "php-symfony-config"},
          {"reference": "php-symfony-console"},
          {"reference": "php-symfony-css-selector"},
          {"reference": "php-symfony-dependency-injection"},
          {"reference": "php-symfony-dom-crawler"},
          {"reference": "php-symfony-dotenv"},
          {"reference": "php-symfony-error-handler"},
          {"reference": "php-symfony-event-dispatcher"},
          {"reference": "php-symfony-expression-language"},
          {"reference": "php-symfony-filesystem"},
          {"reference": "php-symfony-finder"},
          {"reference": "php-symfony-form"},
          {"reference": "php-symfony-html-sanitizer"},
          {"reference": "php-symfony-http-client"},
          {"reference": "php-symfony-http-foundation"},
          {"reference": "php-symfony-http-kernel"},
          {"reference": "php-symfony-intl"},
          {"reference": "php-symfony-ldap"},
          {"reference": "php-symfony-lock"},
          {"reference": "php-symfony-mailer"},
          {"reference": "php-symfony-messenger"},
          {"reference": "php-symfony-mime"},
          {"reference": "php-symfony-notifier"},
          {"reference": "php-symfony-options-resolver"},
          {"reference": "php-symfony-password-hasher"},
          {"reference": "php-symfony-process"},
          {"reference": "php-symfony-property-access"},
          {"reference": "php-symfony-property-info"},
          {"reference": "php-symfony-rate-limiter"},
          {"reference": "php-symfony-remote-event"},
          {"reference": "php-symfony-routing"},
          {"reference": "php-symfony-runtime"},
          {"reference": "php-symfony-scheduler"},
          {"reference": "php-symfony-security-core"},
          {"reference": "php-symfony-security-csrf"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}