Linux Distros Unpatched Vulnerability : CVE-2026-121623

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

include('compat.inc');

if (description)
{
  script_id(377472);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/07");

  script_cve_id("CVE-2026-121623");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-121623");

  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 Serializer component DataUriNormalizer::denormalize() matches the data: scheme with a case-
    sensitive regular expression, allowing a value with an uppercase scheme, such as
    DATA:,/../../../etc/passwd, to bypass it, resulting in Arbitrary Local File Read through Path Traversal 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. A
    value whose scheme is not lowercase data: are treated as a local file path and opened instead of being
    decoded as inline data, so the resulting File, \SplFileInfo, or \SplFileObject points at a file on the
    server, which the application then handles as the uploaded content. Any endpoint that deserializes
    untrusted input into one of these types is affected. FrameworkBundle registers DataUriNormalizer ahead of
    ObjectNormalizer by default. A single request with a crafted DATA: value is enough to read arbitrary local
    files that the application can access, with no authentication needed if the endpoint is public.
    (CVE-2026-121623)

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-2026-121623");
  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:L/AC:L/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N");
  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:N/UI:N/VC:H/VI:N/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-2026-121623");

  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_NOTE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}