Linux Distros Unpatched Vulnerability : CVE-2026-82562

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

include('compat.inc');

if (description)
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  script_id(341597);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/30");

  script_cve_id("CVE-2026-82562");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-82562");

  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 When `qs.parse` is called with `comma: true` and `throwOnLimitExceeded: true`, a comma-
    separated value under a bracket-push key (`a[]=1,2,3,4`) is split into an array without being compared
    against `arrayLimit`, while the same value under a flat key (`a=1,2,3,4`), an indexed key (`a[0]=`), a
    nested key (`a[b]=`), or a dotted key (`a.b=` with `allowDots`) throws the documented `RangeError`. A
    single parameter such as `a[]=1,2,2,...` therefore produces an inner array of arbitrary length even though
    the caller opted into the hard limit. This is the `[]=` key form that the fix for CVE-2026-2391 (qs
    6.14.2) did not cover. ### Details In `lib/parse.js`, a comma-separated value under a `[]=` key is split
    and then wrapped as a single nested element (`val = [val]`, so that each `a[]=x,y` group counts as one
    element of the outer array). The `arrayLimit` check that 6.14.2 added for comma values runs after that
    wrap, so for `[]=` parts it only ever saw the wrapper of length 1. 6.15.3 added a pre-split comma count so
    that an oversized value throws before it is allocated, but gated it on an `isFlatArrayValue` flag that
    `parseValues` set to `false` for any part containing `[]=`, and did not pass it for object-valued input,
    so the gap remained. #### PoC ```js var qs = require('qs'); var options = { comma: true, arrayLimit: 3,
    throwOnLimitExceeded: true }; qs.parse('a=1,2,3,4', options); // RangeError: Array limit exceeded. Only 3
    elements allowed in an array. qs.parse('a[]=1,2,3,4', options); // { a: [ [ '1', '2', '3', '4' ] ] } (no
    throw) qs.parse('a[]=' + '1,'.repeat(1000000) + '1', { comma: true, arrayLimit: 20, throwOnLimitExceeded:
    true }); // no throw; a 1,000,001-element inner array is allocated ``` #### Fix `lib/parse.js`, applied in
    8859c37 on `main` and released as v6.16.0: the `isFlatArrayValue` gate is removed, so every comma-split
    value is counted against `arrayLimit` before splitting regardless of key form. An in-limit group under
    `a[]=` still counts as one element of the outer array, and the default (`throwOnLimitExceeded: false`)
    path is unchanged. ### Affected versions `>=6.14.2 <6.16.0`, fixed in v6.16.0. v6.14.2 introduced
    `arrayLimit` enforcement for comma values (the fix for CVE-2026-2391) but only for values not under a
    `[]=` key, and every release from v6.14.2 through v6.15.3 has the same gap. v6.14.0 and v6.14.1, where
    `throwOnLimitExceeded` exists but does not apply to any comma form, are covered by CVE-2026-2391 rather
    than this record. Earlier lines (6.7.x through 6.13.x) have `comma` but no `throwOnLimitExceeded`, so
    there is no hard cap on any comma path to bypass; releases before 6.7.0 have no `comma` option. ### Impact
    An unauthenticated attacker who can reach an application that parses untrusted query strings or urlencoded
    bodies with both `comma: true` and `throwOnLimitExceeded: true` (both non-default) can bypass the
    configured limit with a single `a[]=` parameter and force the parser to allocate an array proportional to
    the request size. The cost is strictly linear in the attacker-supplied bytes (about 0.1 microseconds and 6
    to 7 retained bytes per input byte; the same out-of-memory threshold as the documented default
    `throwOnLimitExceeded: false` path), so a transport-layer request or body size limit bounds it completely
    (and node's default maximum HTTP header size of 16 KB already bounds the request line, so multi-megabyte
    payloads need a body parser). The impact is that an opt-in hard limit fails open on one key spelling, not
    unbounded allocation from a small input. (CVE-2026-82562)

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-2026-82562");
  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: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:H/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-2026-82562");

  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:"2026/08/30");
  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");
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  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');
}