Linux Distros Unpatched Vulnerability : CVE-2026-68494

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

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  script_id(332786);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/06");

  script_cve_id("CVE-2026-68494");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-68494");

  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.

  - The fix released in jackson-core 2.18.6 and 2.21.1 for CVE-2026-18401 (GHSA-72hv-8253-57qq, number length
    constraint bypass in the non-blocking parser) is incomplete. This record covers the remaining bypass. The
    earlier fix wired validateIntegerLength() into a new _setIntLength() helper and invoked it wherever the
    integer portion of a number is decided: a terminator byte arrives, a '.' or 'e'/'E' is seen, or input ends
    inside a fully buffered value. It was not invoked on the attacker-relevant path where the parser runs out
    of input while still inside the MINOR_NUMBER_INTEGER_DIGITS minor state and returns NOT_AVAILABLE to the
    caller. As a result, an attacker who streams JSON to a non-blocking parser in many small chunks, without
    ever sending a terminator byte, keeps the parser inside MINOR_NUMBER_INTEGER_DIGITS indefinitely.
    _textBuffer.expandCurrentSegment() grows the accumulator on every chunk while validateIntegerLength() is
    never called. The accumulator is bounded only by maxStringLength (20 MiB by default) rather than by
    maxNumberLength (1000 by default), an amplification of roughly 20,000x over the documented limit. Because
    Java char values occupy two bytes, a single connection can be driven to approximately 40 MiB of heap
    before the validator finally fires when the value completes. The equivalent fraction-path code is correct:
    _finishFloatFraction() calls _setFractLength() before its NOT_AVAILABLE return. The missing call affects
    the integer-digit paths in _startPositiveNumber(), _startNegativeNumber() and _finishNumberIntegralPart()
    in NonBlockingUtf8JsonParserBase. Impact: reactive frameworks such as Spring WebFlux/Reactor, Quarkus,
    Helidon and Vert.x feed inbound HTTP or gRPC bytes to the async parser as they arrive, which is precisely
    the chunked-feed shape required. Operators who set StreamReadConstraints.maxNumberLength expecting it to
    cap memory per number value do not get that guarantee; memory accumulates per concurrent connection and
    attacker-controlled concurrency can exhaust the JVM heap. The synchronous parsers (UTF8StreamJsonParser,
    ReaderBasedJsonParser) and the async parser operating on complete input are not affected. Exploitation
    requires only the ability to stream data to a parsing endpoint; no privileges or user interaction are
    needed. This issue affects com.fasterxml.jackson.core:jackson-core from version 2.15.0 through 2.18.7, and
    from 2.19.0 through 2.21.3, and tools.jackson.core:jackson-core from 3.0.0 through 3.1.3. Versions prior
    to 2.15.0 are not affected, because StreamReadConstraints -- which defines the maxNumberLength setting --
    was first introduced in jackson-core 2.15.0, so no such constraint exists to be bypassed in earlier
    releases. Note that GHSA-r7wm-3cxj-wff9 states the affected 2.x range without a lower bound. The 2.22.x
    and 3.2.x release lines are not affected: those branches were created after the fix commit landed on
    2026-05-21 and therefore contain it from their initial releases (2.22.0, tagged 2026-06-03, and 3.2.0,
    tagged 2026-06-08). (CVE-2026-68494)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/security/cve/cve-2026-68494");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-68494");
  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:L/PR:N/UI:N/S:U/C:N/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
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  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-68494");

  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:"2026/08/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/05");

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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:ldapjdk");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pki-base-java");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pki-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pki-symkey");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:pki-tools");
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  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:python3-pki");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:centos:centos:resteasy");
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  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/CentOS Linux-8", "Host/OS/Red Hat Enterprise Linux-8", "Host/OS/Red Hat Enterprise Linux-9", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-26.04");

  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/CentOS/rpm-list")) && empty_or_null(get_one_kb_item("Host/Debian/dpkg-l")) && empty_or_null(get_one_kb_item("Host/RedHat/rpm-list"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "Ubuntu Linux-26.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "26.04",
        "pkgs": [
          {"reference": "jackson-core"}
        ]
      }
    ]
  },
  "CentOS Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "idm-jss"},
          {"reference": "idm-jss-javadoc"},
          {"reference": "idm-ldapjdk"},
          {"reference": "idm-ldapjdk-javadoc"},
          {"reference": "idm-pki-acme"},
          {"reference": "idm-pki-base"},
          {"reference": "idm-pki-base-java"},
          {"reference": "idm-pki-ca"},
          {"reference": "idm-pki-kra"},
          {"reference": "idm-pki-server"},
          {"reference": "idm-pki-symkey"},
          {"reference": "idm-pki-tools"},
          {"reference": "idm-tomcatjss"},
          {"reference": "jss"},
          {"reference": "jss-javadoc"},
          {"reference": "ldapjdk"},
          {"reference": "ldapjdk-javadoc"},
          {"reference": "pki-acme"},
          {"reference": "pki-base"},
          {"reference": "pki-base-java"},
          {"reference": "pki-ca"},
          {"reference": "pki-core"},
          {"reference": "pki-kra"},
          {"reference": "pki-server"},
          {"reference": "pki-symkey"},
          {"reference": "pki-tools"},
          {"reference": "python3-idm-pki"},
          {"reference": "python3-pki"},
          {"reference": "resteasy"},
          {"reference": "resteasy-javadoc"},
          {"reference": "tomcatjss"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-8": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "8",
        "pkgs": [
          {"reference": "idm-jss"},
          {"reference": "idm-jss-javadoc"},
          {"reference": "idm-ldapjdk"},
          {"reference": "idm-ldapjdk-javadoc"},
          {"reference": "idm-pki-acme"},
          {"reference": "idm-pki-base"},
          {"reference": "idm-pki-base-java"},
          {"reference": "idm-pki-ca"},
          {"reference": "idm-pki-kra"},
          {"reference": "idm-pki-server"},
          {"reference": "idm-pki-symkey"},
          {"reference": "idm-pki-tools"},
          {"reference": "idm-tomcatjss"},
          {"reference": "jss"},
          {"reference": "jss-javadoc"},
          {"reference": "ldapjdk"},
          {"reference": "ldapjdk-javadoc"},
          {"reference": "pki-acme"},
          {"reference": "pki-base"},
          {"reference": "pki-base-java"},
          {"reference": "pki-ca"},
          {"reference": "pki-core"},
          {"reference": "pki-kra"},
          {"reference": "pki-server"},
          {"reference": "pki-symkey"},
          {"reference": "pki-tools"},
          {"reference": "python3-idm-pki"},
          {"reference": "python3-pki"},
          {"reference": "resteasy"},
          {"reference": "resteasy-javadoc"},
          {"reference": "tomcatjss"}
        ]
      }
    ]
  },
  "Red Hat Enterprise Linux-9": {
    "package_manager": "rpm-list",
    "constraints": [
      {
        "release": "9",
        "pkgs": [
          {"reference": "idm-pki-acme"},
          {"reference": "idm-pki-base"},
          {"reference": "idm-pki-ca"},
          {"reference": "idm-pki-est"},
          {"reference": "idm-pki-java"},
          {"reference": "idm-pki-kra"},
          {"reference": "idm-pki-server"},
          {"reference": "idm-pki-tools"},
          {"reference": "pki-acme"},
          {"reference": "pki-base"},
          {"reference": "pki-base-java"},
          {"reference": "pki-ca"},
          {"reference": "pki-core"},
          {"reference": "pki-kra"},
          {"reference": "pki-server"},
          {"reference": "pki-symkey"},
          {"reference": "pki-tools"},
          {"reference": "python3-idm-pki"},
          {"reference": "python3-pki"}
        ]
      }
    ]
  }
};

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');
}