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Advisory severityHigh7.5Red Hat Linux

High [CVE-2026-5680] Undertow-core: undertow: denial of service via websocket permessage-deflate processing

This high-severity Red Hat Linux advisory covers CVE-2026-5680 affecting Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-5680 Source published Source updated

VulniPulse record published

CVE-2026-5680
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
Open source advisory

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Summary

A flaw was found in Undertow. A remote attacker could exploit this vulnerability by sending specially crafted WebSocket messages with permessage-deflate negotiated.

This could lead to excessive memory consumption due to the PerMessageDeflateFunction.largerBuffer() method using exponential doubling, resulting in a Denial of Service (DoS) for the affected application. Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Weakness: CWE-770.

Affected Red Hat products: Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 10; Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8; Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9; Red Hat build of Apache Camel for Spring Boot 4; Red Hat Data Grid 8; Red Hat Enterprise Linux 9; Red Hat JBoss Enterprise Application Platform 7; Red Hat JBoss Enterprise Application Platform Expansion Pack; Red Hat Process Automation 7; Red Hat Single Sign-On 7.

Will not fix / out of support: Red Hat JBoss Enterprise Application Platform 7; Red Hat JBoss Enterprise Application Platform Expansion Pack; Red Hat Process Automation 7; Red Hat Single Sign-On 7. Red Hat fixing advisory: RHSA-2026:70230, RHSA-2026:70228, RHSA-2026:70229.

Affected products named by the advisory: Red Hat package: resteasy.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Fixed versions
  • eap8-activemq-artemis-0:2.40.0-8.redhat_00024.1.el10eap
  • eap8-apache-cxf-0:4.1.7-1.SP1_redhat_00001.1.el10eap
  • eap8-artemis-wildfly-integration-0:2.0.5-1.Final_redhat_00001.1.el10eap
  • eap8-bouncycastle-0:1.85.0-1.redhat_00001.1.el10eap
  • eap8-cryptacular-0:1.2.7-1.redhat_00002.1.el10eap
  • eap8-eap-product-conf-parent-0:801.8.0-1.GA_redhat_00001.1.el10eap
  • eap8-hibernate-0:6.6.54-1.Final_redhat_00001.1.el10eap
  • eap8-httpcomponents-asyncclient-0:4.1.5-5.redhat_00008.1.el10eap
  • eap8-ironjacamar-0:3.0.22-1.Final_redhat_00001.1.el10eap
  • eap8-jackson-annotations-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-core-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-databind-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-dataformats-text-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-jaxrs-providers-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-modules-base-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jackson-modules-java8-0:2.18.9-1.redhat_00003.1.el10eap
  • eap8-jakarta-xml-bind-api-0:4.0.5-1.redhat_00001.1.el10eap
  • eap8-jaxb-0:4.0.7-4.redhat_00001.1.el10eap
  • eap8-jaxbintros-0:2.1.0-1.redhat_00001.1.el10eap
  • eap8-jboss-logging-0:3.6.3-1.Final_redhat_00001.1.el10eap
  • eap8-jboss-remoting-0:5.0.31-1.SP2_redhat_00001.1.el10eap
  • eap8-jbossws-api-0:3.1.0-1.Final_redhat_00001.1.el10eap
  • eap8-jbossws-common-tools-0:2.2.0-1.Final_redhat_00001.1.el10eap
  • eap8-jbossws-cxf-0:7.4.0-1.Final_redhat_00001.1.el10eap
  • eap8-jbossws-jaxws-undertow-httpspi-0:3.0.1-1.Final_redhat_00001.1.el10eap
  • eap8-jbossws-spi-0:5.1.0-1.Final_redhat_00001.1.el10eap
  • eap8-jsf-impl-0:4.0.11-2.SP1_redhat_00001.1.el10eap
  • eap8-log4j-0:2.25.4-1.redhat_00003.1.el10eap
  • eap8-neethi-0:3.2.2-1.redhat_00001.1.el10eap
  • eap8-netty-0:4.1.136-1.Final_redhat_00001.1.el10eap
  • eap8-netty-transport-native-epoll-0:4.1.136-1.Final_redhat_00001.1.el10eap
  • eap8-nimbus-jose-jwt-0:9.37.4-1.redhat_00001.1.el10eap
  • eap8-parsson-0:1.1.9-1.redhat_00001.1.el10eap
  • eap8-saaj-impl-0:3.0.6-1.redhat_00001.1.el10eap
  • eap8-slf4j-0:2.0.18-1.redhat_00001.1.el10eap
  • eap8-undertow-0:2.3.26-2.SP3_redhat_00001.1.el10eap
  • eap8-wildfly-0:8.1.8-9.GA_redhat_00006.1.el10eap
  • eap8-wildfly-elytron-0:2.6.11-1.Final_redhat_00001.1.el10eap
  • eap8-wildfly-javadocs-0:8.1.1-12.GA_redhat_00048.1.el10eap
  • eap8-ws-commons-XmlSchema-0:2.3.2-1.redhat_00001.1.el10eap
  • RHSA-2026:70230
  • RHSA-2026:70228
  • RHSA-2026:70229

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • To mitigate this issue, configure the PerMessageDeflateHandshake to limit the maximum decompressed buffer size. This can be achieved by setting the maxDecompressedBufferSize parameter to a reasonable value (e.g., 10 MB) in the PerMessageDeflateHandshake constructor. This action may require a restart of the affected application or service to take effect.

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

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