CVE-2026-93492

Io.netty/netty-codec-http2: netty: http/2 hpackencoder dos with large table size

Published Sep 18, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in Netty's HTTP/2 HpackEncoder. A remote attacker can exploit this by sending HTTP/2 SETTINGS frames with a very large MAX_HEADER_TABLE_SIZE. This causes the HpackEncoder to store an excessive number of unique headers, leading to increased CPU usage and memory consumption, ultimately resulting in a Denial of Service (DoS).

Remediation

Vendor Workaround

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.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak: cpe:/a:redhat:build_keycloak:26.4::el9
cpe:/a:redhat:build_keycloak:26.6::el9
References
Type Values Removed Values Added
First Time appeared Redhat jboss Enterprise Application Platform Xp
CPEs cpe:/a:redhat:jboss_enterprise_application_platform_xp:6.0
Vendors & Products Redhat jboss Enterprise Application Platform Xp
References
Type Values Removed Values Added
First Time appeared Redhat jbosseapxp
CPEs cpe:/a:redhat:jbosseapxp
Vendors & Products Redhat jbosseapxp
Type Values Removed Values Added
CPEs cpe:/a:redhat:debezium:3 cpe:/a:redhat:debezium:3.6
References
Type Values Removed Values Added
First Time appeared Redhat quarkus
CPEs cpe:/a:redhat:quarkus:3.27::el8
cpe:/a:redhat:quarkus:3.33::el8
Vendors & Products Redhat quarkus
Type Values Removed Values Added
First Time appeared Io.netty
Io.netty netty-codec-http2
Redhat amq Broker 7
Redhat build Of Apache Camel For Quarkus
Redhat build Of Apache Camel For Spring Boot
Redhat build Of Apicurio Registry
Redhat build Of Debezium 3
Redhat build Of Keycloak
Redhat build Of Quarkus
Redhat data Grid 8
Redhat quay 3
Redhat single Sign-on
Vendors & Products Io.netty
Io.netty netty-codec-http2
Redhat amq Broker 7
Redhat build Of Apache Camel For Quarkus
Redhat build Of Apache Camel For Spring Boot
Redhat build Of Apicurio Registry
Redhat build Of Debezium 3
Redhat build Of Keycloak
Redhat build Of Quarkus
Redhat data Grid 8
Redhat quay 3
Redhat single Sign-on
Type Values Removed Values Added
CPEs cpe:/a:redhat:quarkus:3
Vendors & Products Redhat quarkus
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in Netty's HTTP/2 HpackEncoder. A remote attacker can exploit this by sending HTTP/2 SETTINGS frames with a very large MAX_HEADER_TABLE_SIZE. This causes the HpackEncoder to store an excessive number of unique headers, leading to increased CPU usage and memory consumption, ultimately resulting in a Denial of Service (DoS).
Title Io.netty/netty-codec-http2: netty: http/2 hpackencoder dos with large table size
First Time appeared Redhat
Redhat amq Broker
Redhat apicurio Registry
Redhat build Keycloak
Redhat camel Quarkus
Redhat camel Spring Boot
Redhat debezium
Redhat jboss Data Grid
Redhat jboss Enterprise Application Platform
Redhat jboss Fuse
Redhat quarkus
Redhat red Hat Single Sign On
Weaknesses CWE-1035
CPEs cpe:/a:redhat:amq_broker:7
cpe:/a:redhat:apicurio_registry:3
cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:camel_quarkus:3
cpe:/a:redhat:camel_spring_boot:4
cpe:/a:redhat:debezium:3
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jboss_enterprise_application_platform:7
cpe:/a:redhat:jboss_enterprise_application_platform:8
cpe:/a:redhat:jboss_fuse:7
cpe:/a:redhat:quarkus:3
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat amq Broker
Redhat apicurio Registry
Redhat build Keycloak
Redhat camel Quarkus
Redhat camel Spring Boot
Redhat debezium
Redhat jboss Data Grid
Redhat jboss Enterprise Application Platform
Redhat jboss Fuse
Redhat quarkus
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}