Linux Distros Unpatched Vulnerability : CVE-2026-15176

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

include('compat.inc');

if (description)
{
  script_id(365995);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/15");

  script_cve_id("CVE-2026-15176");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-15176");

  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.

  - A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the
    alias directive together with rewrite and a set or return directive referencing the $request_filename
    variable. Alternatively, the same result could be achieved when the $request_filename variable is used in
    an access log format directive. An unauthenticated attacker along with conditions beyond their control can
    exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the
    NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with
    Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This
    vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to
    possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.
    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-15176)

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-2026-15176");
  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:H/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/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:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/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-2026-15176");

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

  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:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:nginx");
  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", "Host/OS/Debian Linux-14");

  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": "libnginx-mod-http-geoip"},
          {"reference": "libnginx-mod-http-image-filter"},
          {"reference": "libnginx-mod-http-perl"},
          {"reference": "libnginx-mod-http-xslt-filter"},
          {"reference": "libnginx-mod-mail"},
          {"reference": "libnginx-mod-stream"},
          {"reference": "libnginx-mod-stream-geoip"},
          {"reference": "nginx"},
          {"reference": "nginx-common"},
          {"reference": "nginx-core"},
          {"reference": "nginx-dev"},
          {"reference": "nginx-doc"},
          {"reference": "nginx-extras"},
          {"reference": "nginx-full"},
          {"reference": "nginx-light"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "libnginx-mod-http-geoip"},
          {"reference": "libnginx-mod-http-image-filter"},
          {"reference": "libnginx-mod-http-perl"},
          {"reference": "libnginx-mod-http-xslt-filter"},
          {"reference": "libnginx-mod-mail"},
          {"reference": "libnginx-mod-stream"},
          {"reference": "libnginx-mod-stream-geoip"},
          {"reference": "nginx"},
          {"reference": "nginx-common"},
          {"reference": "nginx-core"},
          {"reference": "nginx-dev"},
          {"reference": "nginx-doc"},
          {"reference": "nginx-extras"},
          {"reference": "nginx-full"},
          {"reference": "nginx-light"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "libnginx-mod-http-geoip"},
          {"reference": "libnginx-mod-http-image-filter"},
          {"reference": "libnginx-mod-http-perl"},
          {"reference": "libnginx-mod-http-xslt-filter"},
          {"reference": "libnginx-mod-mail"},
          {"reference": "libnginx-mod-stream"},
          {"reference": "libnginx-mod-stream-geoip"},
          {"reference": "nginx"},
          {"reference": "nginx-common"},
          {"reference": "nginx-core"},
          {"reference": "nginx-dev"},
          {"reference": "nginx-doc"},
          {"reference": "nginx-extras"},
          {"reference": "nginx-full"},
          {"reference": "nginx-light"}
        ]
      }
    ]
  }
};

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');
}