Netty HpackEncoder DoS via oversized SETTINGS MAX_HEADER_TABLE_SIZE
CVE-2026-93492 Published on September 18, 2026

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

NVD

Vulnerability Analysis

CVE-2026-93492 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Timeline

Reported to Red Hat.

Made public.

Weakness Type

OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities

Weaknesses in this category are related to the A9 category in the OWASP Top Ten 2017.


Products Associated with CVE-2026-93492

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Red Hat Amq Broker
 
Red Hat Camel Quarkus
 
Red Hat Camel Spring Boot
 
Red Hat Apicurio Registry
 
Red Hat Debezium
 
Red Hat Build Keycloak
 
Red Hat Quarkus
 
Red Hat Jboss Data Grid
 
Red Hat Jboss Fuse
 
Red Hat Jboss Enterprise Application Platform
 
Red Hat Single Sign On
 

Affected Versions

Red Hat AMQ Broker 7: Red Hat build of Apache Camel 4 for Quarkus 3: Red Hat build of Apache Camel for Spring Boot 4: Red Hat build of Apicurio Registry 3: Red Hat build of Debezium 3: Red Hat Build of Keycloak: Red Hat build of Quarkus: Red Hat Data Grid 8: Red Hat Fuse 7: Red Hat JBoss Enterprise Application Platform 7: Red Hat JBoss Enterprise Application Platform 8: Red Hat Single Sign-On 7: