Linux Distros Unpatched Vulnerability : CVE-2026-8723

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

include('compat.inc');

if (description)
{
  script_id(315208);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/29");

  script_cve_id("CVE-2026-8723");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-8723");

  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.

  - ### Summary `qs.stringify` throws `TypeError` when called with `arrayFormat: 'comma'` and
    `encodeValuesOnly: true` on an array containing `null` or `undefined`. The throw is synchronous and not
    handled by any of qs's null-related options (`skipNulls`, `strictNullHandling`). ### Details In the comma
    + `encodeValuesOnly` branch, `lib/stringify.js:145` mapped the array through the raw encoder before
    joining: ```js obj = utils.maybeMap(obj, encoder); ``` `utils.encode` (`lib/utils.js:195`) reads
    `str.length` with no null guard, so a `null` or `undefined` element throws `TypeError`. `skipNulls` and
    `strictNullHandling` are both checked in the per-element loop below this line and never get a chance to
    run. Same class of bug as the filter-array path fixed in 0c180a4. The vulnerable shape of the comma +
    `encodeValuesOnly` branch was introduced in 4c4b23d (encode comma values more consistently, PR #463,
    2023-01-19), first released in v6.11.1. #### PoC ```js const qs = require('qs'); qs.stringify({ a: [null,
    'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true }); qs.stringify({ a: [undefined, 'b'] }, {
    arrayFormat: 'comma', encodeValuesOnly: true }); qs.stringify({ a: [null] }, { arrayFormat: 'comma',
    encodeValuesOnly: true }); // TypeError: Cannot read properties of null (reading 'length') // at encode
    (lib/utils.js:195:13) // at Object.maybeMap (lib/utils.js:322:37) // at stringify
    (lib/stringify.js:145:25) ``` #### Fix `lib/stringify.js:145`, applied in 21f80b3 on `main` and released
    as v6.15.2: ```diff - obj = utils.maybeMap(obj, encoder); + obj = utils.maybeMap(obj, function (v) { +
    return v == null ? v : encoder(v); + }); ``` `null` and `undefined` now pass through `maybeMap` unchanged
    and reach the `join(',')` step as-is. For `{ a: [null, 'b'] }` this produces `a=,b`, matching the
    non-`encodeValuesOnly` comma path (which already joins before encoding and produces `a=%2Cb` for the same
    input). Single-element `[null]` arrays still collapse via the existing `obj.join(',') || null` and remain
    subject to `skipNulls` / `strictNullHandling` in the main loop. ### Affected versions `>=6.11.1 <6.15.2` 
    fixed in v6.15.2. The vulnerable code shape was introduced in 4c4b23d and first shipped in v6.11.1.
    Earlier versions  including all of 6.7.x, 6.8.x, 6.9.x, 6.10.x, and 6.11.0  implemented the comma +
    `encodeValuesOnly` path differently (joining before encoding) and are not affected. Empirically verified
    across released versions. ### Impact Application code that calls `qs.stringify` with both `arrayFormat:
    'comma'` and `encodeValuesOnly: true` (both non-default) on input that may contain a `null` or `undefined`
    array element will throw synchronously instead of producing a query string. In a typical Node.js HTTP
    framework (Express, Fastify, Koa, hapi) the sync throw is caught by the framework's error boundary and the
    affected request returns a 500; the worker process does not exit and subsequent requests are unaffected.
    The kills the worker process framing applies only to call sites outside a request-handler error boundary
    (background jobs, startup paths, stream pipelines) or to deployments with framework error handling
    explicitly disabled. The vulnerable input is a `null` or `undefined` entry inside an array; this is
    reachable from JSON request bodies or from application code constructing arrays from user input, but not
    from standard HTML form submissions (which produce strings or omitted fields, not literal `null`).
    (CVE-2026-8723)

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-2026-8723");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-8723");
  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:N/I:N/A:P");
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  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:"2026/05/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/18");

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  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");
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  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
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  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
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  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

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  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
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  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-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "node-qs"}
        ]
      }
    ]
  }
};

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 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');
}