Skip to content
VulniPulse
Sign in
Advisory severityHigh7.5Red Hat Linux

High [CVE-2026-55831] Denial of Service via SPDY SETTINGS frame processing

This high-severity Red Hat Linux advisory covers CVE-2026-55831 affecting Cryostat 4 on RHEL 9, Red Hat AMQ Broker 7.13.6, Red Hat AMQ Broker 7.14.1.

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

CVE-2026-55831 Source published Source updated

VulniPulse record published Record updated

CVE-2026-55831
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

Get an email when Red Hat Linux publishes the next one.

See Red Hat Linux's last 90 days of advisories first. Then choose one product with live alerts free for life, or a free month of real-time alerts on everything with the severity, the fixed version and the vendor's link (card needed, then US$15/month; we email you before the first charge).

Alert me about Red Hat Linux

Summary

Netty is a network application framework for development of protocol servers and clients.

Prior to 4.1.136.Final and 4.2.16.Final, Netty's SPDY SETTINGS decoder accepts a peer-declared SETTINGS entry count up to the 24-bit frame-length limit and materializes every unique setting ID in `DefaultSpdySettingsFrame`, allowing a remote SPDY/3.1 peer to send a syntactically valid roughly 2 MiB SETTINGS frame that creates 262144 map entries and amplifies network input into heap growth and ordered-map insertion work.

A remote attacker, by sending a specially crafted SPDY/3.1 SETTINGS frame, could cause the SPDY SETTINGS decoder to create a large number of map entries. This excessive processing and memory allocation can lead to a denial of service (DoS) due to heap growth and increased CPU usage.

This is an Important denial of service flaw in Netty's SPDY SETTINGS decoder, allowing a remote unauthenticated attacker to exhaust system resources. By sending a specially crafted SPDY/3.1 SETTINGS frame, an attacker can cause excessive memory allocation and CPU usage, leading to a denial of service.

This vulnerability has a low attack complexity and requires no user interaction or privileges. 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 versions
  • < 4.1.136.Final
  • < 4.2.16.Final
  • < 3.1

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

Fixed versions
  • 4.1.136
  • 4.2.16
  • cryostat/cryostat-reports-rhel9:4.2.0-14
  • cryostat/cryostat-rhel9:4.2.0-14
  • cryostat/jfr-datasource-rhel9:4.2.0-14
  • netty-codec-http
  • io.netty/netty-codec-http:4.1.136.Final-redhat-00001
  • 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
  • RHSA-2026:68333
  • RHSA-2026:66545
  • RHSA-2026:66488
  • RHSA-2026:48118
  • RHSA-2026:54622
  • RHSA-2026:76637
  • RHSA-2026:50846
  • RHSA-2026:50848

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Official advisory · high-confidence parse· fetched 1 day ago·verify at source

More Red Hat Linux advisories

All Red Hat Linux advisories

iPhone and Android apps · New on the App Store

Monitor future Red Hat Linux CVEs from your phone.

Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 34 official vendor sources and 160+ reviewed platform categories.

Download on the App StoreGet CVE alerts on AndroidSee app features

Discussion(0)

No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.

Sign in to join the discussion.