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Linux Distros Unpatched Vulnerability : CVE-2026-68494

high Nessus Plugin ID 332786

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

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.

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2026-68494

https://ubuntu.com/security/CVE-2026-68494

Plugin Details

Severity: High

ID: 332786

File Name: unpatched_CVE_2026_68494.nasl

Version: 1.2

Type: Local

Agent: unix

Family: Misc.

Published: 8/5/2026

Updated: 8/6/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.61

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:P

CVSS Score Source: CVE-2026-68494

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 8.3

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:centos:centos:8, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:canonical:ubuntu_linux:jackson-core, p-cpe:/a:centos:centos:idm-jss-javadoc, p-cpe:/a:centos:centos:idm-jss, p-cpe:/a:centos:centos:idm-ldapjdk-javadoc, p-cpe:/a:centos:centos:idm-ldapjdk, p-cpe:/a:centos:centos:idm-pki-acme, p-cpe:/a:centos:centos:idm-pki-base-java, p-cpe:/a:centos:centos:idm-pki-base, p-cpe:/a:centos:centos:idm-pki-ca, p-cpe:/a:centos:centos:idm-pki-est, p-cpe:/a:centos:centos:idm-pki-java, p-cpe:/a:centos:centos:idm-pki-kra, p-cpe:/a:centos:centos:idm-pki-server, p-cpe:/a:centos:centos:idm-pki-symkey, p-cpe:/a:centos:centos:idm-pki-tools, p-cpe:/a:centos:centos:idm-tomcatjss, p-cpe:/a:centos:centos:jss-javadoc, p-cpe:/a:centos:centos:jss, p-cpe:/a:centos:centos:ldapjdk-javadoc, p-cpe:/a:centos:centos:ldapjdk, p-cpe:/a:centos:centos:pki-acme, p-cpe:/a:centos:centos:pki-base-java, p-cpe:/a:centos:centos:pki-base, p-cpe:/a:centos:centos:pki-ca, p-cpe:/a:centos:centos:pki-core, p-cpe:/a:centos:centos:pki-kra, p-cpe:/a:centos:centos:pki-server, p-cpe:/a:centos:centos:pki-symkey, p-cpe:/a:centos:centos:pki-tools, p-cpe:/a:centos:centos:python3-idm-pki, p-cpe:/a:centos:centos:python3-pki, p-cpe:/a:centos:centos:resteasy-javadoc, p-cpe:/a:centos:centos:resteasy, p-cpe:/a:centos:centos:tomcatjss, p-cpe:/a:redhat:enterprise_linux:idm-jss-javadoc, p-cpe:/a:redhat:enterprise_linux:idm-jss, p-cpe:/a:redhat:enterprise_linux:idm-ldapjdk-javadoc, p-cpe:/a:redhat:enterprise_linux:idm-ldapjdk, p-cpe:/a:redhat:enterprise_linux:idm-pki-acme, p-cpe:/a:redhat:enterprise_linux:idm-pki-base-java, p-cpe:/a:redhat:enterprise_linux:idm-pki-base, p-cpe:/a:redhat:enterprise_linux:idm-pki-ca, p-cpe:/a:redhat:enterprise_linux:idm-pki-est, p-cpe:/a:redhat:enterprise_linux:idm-pki-java, p-cpe:/a:redhat:enterprise_linux:idm-pki-kra, p-cpe:/a:redhat:enterprise_linux:idm-pki-server, p-cpe:/a:redhat:enterprise_linux:idm-pki-symkey, p-cpe:/a:redhat:enterprise_linux:idm-pki-tools, p-cpe:/a:redhat:enterprise_linux:idm-tomcatjss, p-cpe:/a:redhat:enterprise_linux:jss-javadoc, p-cpe:/a:redhat:enterprise_linux:jss, p-cpe:/a:redhat:enterprise_linux:ldapjdk-javadoc, p-cpe:/a:redhat:enterprise_linux:ldapjdk, p-cpe:/a:redhat:enterprise_linux:pki-acme, p-cpe:/a:redhat:enterprise_linux:pki-base-java, p-cpe:/a:redhat:enterprise_linux:pki-base, p-cpe:/a:redhat:enterprise_linux:pki-ca, p-cpe:/a:redhat:enterprise_linux:pki-core, p-cpe:/a:redhat:enterprise_linux:pki-kra, p-cpe:/a:redhat:enterprise_linux:pki-server, p-cpe:/a:redhat:enterprise_linux:pki-symkey, p-cpe:/a:redhat:enterprise_linux:pki-tools, p-cpe:/a:redhat:enterprise_linux:python3-idm-pki, p-cpe:/a:redhat:enterprise_linux:python3-pki, p-cpe:/a:redhat:enterprise_linux:resteasy-javadoc, p-cpe:/a:redhat:enterprise_linux:resteasy, p-cpe:/a:redhat:enterprise_linux:tomcatjss

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 8/4/2026

Reference Information

CVE: CVE-2026-68494