Linux Distros Unpatched Vulnerability : CVE-2026-68498

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

include('compat.inc');

if (description)
{
  script_id(366852);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/19");

  script_cve_id("CVE-2026-68498");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-68498");

  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.

  - StreamReadConstraints.maxNameLength (default 50,000 characters) is intended to bound how much memory a
    single JSON Object property name can consume while being parsed, independently of the much larger
    maxStringLength (default 100,000,000 characters) that bounds ordinary string values. For parsers built
    over character input  Reader, String or char[] sources, all served by ReaderBasedJsonParser  that bound
    is not applied while the name is being accumulated. The code path instead re-uses the string-value length
    check, which is roughly 2000x larger by default. In the character-input slow path,
    ReaderBasedJsonParser._parseName2() accumulates the name into the TextBuffer and, when a segment fills,
    calls TextBuffer.finishCurrentSegment(), which validates only maxStringLength. The correct check,
    StreamReadConstraints.validateNameLength(int), is reached afterwards in
    CharsToNameCanonicalizer.findSymbol(), once the entire name has been scanned to its closing quote. By that
    point the full name  up to maxStringLength characters  has already been buffered in memory. A remote
    attacker who can have a single sufficiently long JSON Object property name parsed through this path can
    force allocation on the order of 100,000,000 characters (approximately 200 MB, with segment bookkeeping
    pushing real peak usage higher) before any StreamConstraintsException is thrown, instead of the
    approximately 50,000-character (about 100 KB) bound the API promises. Repeating this across concurrent
    requests can exhaust the heap and crash the process. No authentication or user interaction is required.
    Because StreamReadConstraints.maxDocumentLength is disabled by default (-1), nothing else bounds the token
    first, so the issue is exploitable under default configuration. Byte-input parsers are not affected:
    UTF8StreamJsonParser, UTF8DataInputJsonParser and the non-blocking (async) parsers re-validate
    maxNameLength on every growth of the name-decode buffer via ParserBase._growNameDecodeBuffer(), rejecting
    an oversized name after allocating only tens of kilobytes. Applications are exposed when untrusted JSON is
    parsed from a String, Reader or char[]  for example an HTTP request body already read into a String 
    rather than from raw UTF-8 bytes. This issue affects com.fasterxml.jackson.core:jackson-core from 2.16.0
    and tools.jackson.core:jackson-core from 3.0.0. Releases before 2.16.0 are not affected, because
    StreamReadConstraints.maxNameLength was first introduced in jackson-core 2.16.0. (CVE-2026-68498)

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-2026-68498");
  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:C");
  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:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-68498");

  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:"2026/08/23");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/17");

  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:jackson-core");
  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": "libjackson2-core-java"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "libjackson2-core-java"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "libjackson2-core-java"}
        ]
      }
    ]
  }
};

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');
}