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Fencer Vulns
high 8.7

CVE-2026-68494 json

jackson-core: Async parser maxNumberLength bypass via chunked digit accumulation (incomplete fix for CVE-2026-18401 / GHSA-72hv-8253-57qq)

published 2026-07-21 3 mo ago modified 2026-10-23 16 d ago also GHSA-r7wm-3cxj-wff9 , EUVD-2026-52703

cvss
8.7
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

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).

Patch / fix

  • maven com.fasterxml.jackson.core:jackson-core 2.18.8, 2.21.4
  • maven tools.jackson.core:jackson-core 3.1.4
  • FasterXML jackson-core 2.18.8, 2.21.4, 3.1.4
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el9sso
  • rh-sso7-keycloak red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7.6 18.0.20-1.redhat_00001.1.el7sso
  • eap8-jaxb jboss enterprise application platform 8.1 4.0.7-4.redhat_00001.1.el10eap
  • eap8-txw2 jboss enterprise application platform 8.1 4.0.7-4.redhat_00001.1.el10eap

red hat advisories RHSA-2026:76129RHSA-2026:76130RHSA-2026:76128RHSA-2026:70230RHSA-2026:70229RHSA-2026:70228

  • jackson-databind SLES for SAP applications 16.0, SLES 16.0 2.18.11-160000.1.1
  • jackson-core SLES for SAP applications 16.0, SLES 16.0 2.18.11-160000.1.1
  • jackson-annotations SLES for SAP applications 16.0, SLES 16.0 2.18.11-160000.1.1
  • jackson-core SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.18.11-150200.3.30.1
  • jackson-databind SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.18.11-150200.3.36.1
  • jackson-annotations SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.18.11-150200.3.28.1
  • jackson-dataformat-xml SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.18.11-150200.5.8.1
  • jackson-dataformats-binary SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 2.18.11-150200.3.29.1

suse advisories SUSE-SU-2026:24149-1SUSE-SU-2026:4394-1

  • jackson-databind openSUSE Leap 16.0 2.18.11-160000.1.1
  • jackson-core openSUSE Leap 16.0 2.18.11-160000.1.1
  • jackson-annotations openSUSE Leap 16.0 2.18.11-160000.1.1
  • jackson-core openSUSE Tumbleweed 2.18.9-2.1

opensuse advisories openSUSE-SU-2026:22034-1openSUSE-SU-2026:11638-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-68494 updated cvss 7.5

com.fasterxml.jackson.core/jackson-core: tools.jackson.core/jackson-core: jackson-core: Denial of Service via incomplete fix in async JSON parser

  • Red Hat Exploit Intelligence exploit-intelligence/agent-client-rhel9 Red Hat OpenShift Developer Tools and Services jenkins, jenkins-2-plugins Red Hat OpenShift Serverless openshift-serverless-1/kn-ekb-receiver-rhel9, openshift-serverless-1/kn-ekb-dispatcher-rhel9, openshift-serverless-1/kn-eventing-integrations-log-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9, +4 more
    affected: workaround, no fix available
  • Red Hat AI Inference Server rhaii/vllm-gaudi-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat AMQ Broker 7 jackson-core 2.22.1.redhat-00003 Red Hat build of Apache Camel - HawtIO 4 jackson-core 2.22.1.redhat-00003 Red Hat build of Apache Camel 4 for Quarkus 3 jackson-core 2.22.1.redhat-00003 Red Hat build of Apicurio Registry 3 jackson-core 2.22.1.redhat-00003 Red Hat Build of Keycloak rhbk-keycloak-rhel9, rhbk-rhel9-operator, rhbk/keycloak-rhel9, rhbk-openshift-rhel9, keycloak/rhbk-rhel9-operator, rhbk-keycloak-rhel9-operator, +4 more
    affected: workaround, no fix available
  • Red Hat Ceph Storage 6 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +16 more Red Hat Ceph Storage 7 ceph, cephadm, librbd1, librgw2, rbd-nbd, ceph-mib, +16 more Red Hat Ceph Storage 8 ceph, cephadm, liborc1, librbd1, librgw2, rbd-nbd, +18 more Red Hat Ceph Storage 9 ceph, liborc, cephadm, liborc2, librbd1, librgw2, +21 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Certificate System 10 redhat-pki 10.13.14-1.module+el8pki+24697+be195eea Red Hat Certificate System 11 redhat-pki 11.10.0-1.el10_2
    affected: workaround, no fix available
  • Red Hat Data Grid 8 datagrid-datagrid-8-rhel9, redhat-datagrid-server.zip 8.6.2.CR1, redhat-datagrid-maven-repository.zip 8.6.1.CR1
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 9 jackson-core, pki-jackson-core Red Hat Enterprise Linux 10 ceph
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-gaudi-rhel9 Red Hat Fuse 7 jackson-core 2.22.1.redhat-00003 Red Hat JBoss Enterprise Application Platform 7 jackson-core 2.22.1.redhat-00003, jboss-eap-7/eap74-els-openjdk8-openshift-rhel8, jboss-eap-7/eap74-els-openjdk11-openshift-rhel8, jboss-eap-7/eap74-els-openjdk17-openshift-rhel8
    affected: workaround, no fix planned “Will not fix”
show 15 more
  • Red Hat JBoss Enterprise Application Platform 8 jackson-core 2.22.1.redhat-00003, jboss-eap.1-runtime-maven-repository.zip 8.1.0 Red Hat JBoss Web Server 7 jws70-openjdk17-rhel9-openshift, jws70-openjdk21-rhel9-openshift, jboss-webserver-7-jws70-openjdk17-openshift-rhel9, jboss-webserver-7-jws70-openjdk21-openshift-rhel9, jboss-webserver-7/jws70-openjdk17-openshift-rhel9, jboss-webserver-7/jws70-openjdk17-rhel9-openshift, +2 more Red Hat OpenShift AI (RHOAI) rhoai/odh-th06-cpu-torch291-py312-rhel9, rhai-early-access/docling-serve-cuda-rhel9, rhoai/odh-th06-cuda130-torch291-py312-rhel9 Red Hat Satellite 6 puppetserver, candlepin 4.4.25-1.el8sat, candlepin 4.4.25-1.el9sat Red Hat streams for Apache Kafka 3 jackson-core 2.22.1.redhat-00003
    affected: workaround, no fix available
  • Red Hat AMQ Clients 2026.Q3
    fixed: vendor fix RHSA-2026:69459
  • Red Hat Cryostat 4 on RHEL 9 cryostat/cryostat-rhel9 4.2.0-14, cryostat/jfr-datasource-rhel9 4.2.0-14, cryostat/cryostat-reports-rhel9 4.2.0-14
    fixed: vendor fix RHSA-2026:68333
  • Red Hat Middleware Containers for OpenShift rh-sso-7/sso76-openshift-rhel8 7.6-85
    fixed: vendor fix RHSA-2026:76134
  • Red Hat OpenShift Developer Tools and Services 4.12 ocp-tools-4/jenkins-rhel8 1786628667
    fixed: vendor fix RHSA-2026:60247
  • Red Hat OpenShift Developer Tools and Services 4.13 ocp-tools-4/jenkins-rhel8 1786628681
    fixed: vendor fix RHSA-2026:60249
  • Red Hat OpenShift Developer Tools and Services 4.14 ocp-tools-4/jenkins-rhel8 1786533561
    fixed: vendor fix RHSA-2026:60248
  • Red Hat OpenShift Developer Tools and Services 4.15 ocp-tools-4/jenkins-rhel8 1786533565
    fixed: vendor fix RHSA-2026:60239
  • Red Hat OpenShift Developer Tools and Services 4.16 ocp-tools-4/jenkins-rhel9 1787125166
    fixed: vendor fix RHSA-2026:60251
  • Red Hat OpenShift Developer Tools and Services 4.17 ocp-tools-4/jenkins-rhel9 1787124635
    fixed: vendor fix RHSA-2026:60246
  • Red Hat OpenShift Developer Tools and Services 4.18 ocp-tools-4/jenkins-rhel9 1787125069
    fixed: vendor fix RHSA-2026:60250
  • Red Hat OpenShift Developer Tools and Services 4.19 ocp-tools-4/jenkins-rhel9 1787124632
    fixed: vendor fix RHSA-2026:60252
  • Red Hat OpenShift Developer Tools and Services 4.20 ocp-tools-4/jenkins-rhel9 1787124925
    fixed: vendor fix RHSA-2026:60259
  • Red Hat OpenShift Developer Tools and Services 4.21 ocp-tools-4/jenkins-rhel9 1787125311
    fixed: vendor fix RHSA-2026:60254
  • Red Hat OpenShift Developer Tools and Services 4.22 ocp-tools-4/jenkins-rhel9 1787124779
    fixed: vendor fix RHSA-2026:60256

31 more fixed, 35 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/FasterXML/jackson-core/security/advisories/GHSA-r7wm-3cxj-wff9 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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
CNA 4.0 8.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
maven com.fasterxml.jackson.core:jackson-core
<2.18.8
>=2.19.0, <2.21.4
2.18.8
2.21.4
maven tools.jackson.core:jackson-core
>=3.0.0, <3.1.4
3.1.4

Affected products

  • FasterXML jackson-core

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.