Linux Distros Unpatched Vulnerability : CVE-2026-118513

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

include('compat.inc');

if (description)
{
  script_id(376442);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/11/05");

  script_cve_id("CVE-2026-118513");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-118513");

  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.

  - Authentication bypass by spoofing in X509Authenticator and X509AuthenticationListener of 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 allows an attacker
    holding a certificate from the application's trusted CA who can influence the CN to authenticate as an
    arbitrary user of the application, including a privileged one, following an incomplete fix for
    CVE-2026-45063. X509Authenticator extracts the user identifier from the Subject DN (Distinguished Name)
    that the web server passes in $_SERVER['SSL_CLIENT_S_DN']. The fix for CVE-2026-45063 anchored that
    extraction to an RDN (Relative Distinguished Name) boundary, but the regular expression used was not
    escape-aware. The expression runs against an already serialized DN, so it cannot tell an RDN separator
    from a separator character that occurs inside a value. Under RFC 2253, used by Apache and by nginx's
    $ssl_client_s_dn, a comma inside a value is escaped as \, and the expression reads it as a separator
    regardless. RFC 2253 also does not treat / as a separator, so it leaves it bare inside a value, while the
    expression treats every / as one. The legacy X509_NAME_oneline() format, used by Apache's
    LegacyDNStringFormat and by nginx's $ssl_client_s_dn_legacy, is the mirror image: it escapes / as \/ and
    leaves , bare. In that format, a certificate with no emailAddress attribute, or whose poisoned CN precedes
    it, authenticates as the smuggled address. To cover both RFC 2253 and the legacy X509_NAME_oneline()
    format, X509Authenticator and X509AuthenticationListener now split the DN into RDNs before looking for the
    attribute, instead of matching the attribute against the serialized string. They select the separator from
    the serialization, split on unescaped occurrences of that separator only, unescape each RDN afterwards
    with the rules of its format, and require the attribute to span a whole RDN. The accepted value grammar is
    unchanged. Applications that pass a per-attribute user key (such as SSL_CLIENT_S_DN_Email) and deployments
    whose CA generates or validates the subject are not affected by this vulnerability. (CVE-2026-118513)

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-2026-118513");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-118513");
  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:N/C:P/I:P/A:P");
  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:N/UI:N/S:U/C:N/I:H/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:L/UI:N/VC:H/VI:H/VA:H/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-2026-118513");

  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:"2026/11/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/11/05");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  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:"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:"cpe:/o:canonical:ubuntu_linux:26.10");
  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:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:symfony");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:symfony");
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  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", "Host/OS/Debian Linux-14", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-26.04", "Host/OS/Ubuntu Linux-26.10");

  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-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "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-emoji"},
          {"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-json-path"},
          {"reference": "php-symfony-json-streamer"},
          {"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-object-mapper"},
          {"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"}
        ]
      }
    ]
  },
  "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"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.10",
        "pkgs": [
          {"reference": "symfony"}
        ]
      }
    ]
  }
};

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