Linux Distros Unpatched Vulnerability : CVE-2026-82417

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

include('compat.inc');

if (description)
{
  script_id(341603);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/30");

  script_cve_id("CVE-2026-82417");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-82417");

  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 a `TypeError` when it serializes an object whose own `constructor`
    property has a truthy, non-callable `isBuffer` member. `utils.isBuffer` duck-types buffers by calling
    `obj.constructor.isBuffer(obj)` after checking only that the property is truthy, so a value such as `{
    constructor: { isBuffer: x } }` makes the call throw `TypeError: obj.constructor.isBuffer is not a
    function`. ### Details `lib/stringify.js:127` calls `utils.isBuffer` on every non-primitive value it
    serializes. `utils.isBuffer` (`lib/utils.js:332`) reads `obj.constructor.isBuffer` and invokes it without
    verifying that it is a function. `constructor` and `isBuffer` are ordinary property names, so any object
    carrying them as own properties reaches the unchecked call. Such an object can be built from untrusted
    input. `qs.parse(x[constructor][isBuffer]=y, { plainObjects: true })` or `{ allowPrototypes: true }`
    keeps the `constructor` key as an own property (the default parse options drop it), and
    `JSON.parse({\a\:{\constructor\:{\isBuffer\:\x\}}})` produces the same shape with no qs option
    involved. Express 4 with its default `query parser` setting and body-parser with `extended: true` both
    call `qs.parse` with `allowPrototypes: true`, so on those stacks `req.query` and `req.body` can carry the
    shape directly. #### PoC ```js var qs = require(qs); qs.stringify(qs.parse(x[constructor][isBuffer]=y,
    { plainObjects: true })); qs.stringify(JSON.parse({\a\:{\constructor\:{\isBuffer\:\x\}}})); //
    TypeError: obj.constructor.isBuffer is not a function // at Object.isBuffer (lib/utils.js:332:78) // at
    stringify (lib/stringify.js:127:45) ``` #### Fix `lib/utils.js`, applied in e83d321 on `main` and released
    as v6.16.0: ```diff - return !!(obj.constructor && obj.constructor.isBuffer &&
    obj.constructor.isBuffer(obj)); + return !!(obj.constructor && typeof obj.constructor.isBuffer ===
    function && obj.constructor.isBuffer(obj)); ``` Real `Buffer`, `safer-buffer`, and browserify `buffer`
    polyfill instances serialize exactly as before; only the throw is removed. ### Affected versions `>=2.2.5
    <6.16.0`, fixed in v6.16.0. The unguarded duck-type was introduced in 3768a75 and first shipped in v2.2.5
    (September 2014). v2.2.4 and earlier used `Buffer.isBuffer` and are not affected. Every release from
    v2.2.5 through v6.15.3 contains the unguarded call. ### Impact An unauthenticated request can make any
    code path that re-serializes attacker-influenced data with `qs.stringify` (for example, rebuilding a query
    string from `req.query` for a redirect or an upstream request, or serializing a parsed JSON body) throw
    synchronously. In a typical Node.js HTTP framework the throw is caught by the framework error boundary and
    the affected request returns a 500; the process survives and other requests are unaffected. Where the call
    runs outside an error boundary, such as an `async` Express 4 handler (where the throw becomes an unhandled
    promise rejection) or a background job, the process exits, so the impact in that case depends on the
    application error handling rather than on qs. (CVE-2026-82417)

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-2026-82417");
  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:N/A:L");
  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:N/VI:N/VA:L/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-2026-82417");

  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:"2026/08/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  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:node-qs");
  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-11", "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-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"}
        ]
      }
    ]
  }
};

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');
}