CVE-2026-93492

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

publishedCWE-1035

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).

Technical severity5.3 mediumCVSS 3.1 · CNA: redhat

Published2026-09-18Source updated 2026-11-04

Collected2026-11-042 attributed sources

Fixes and workarounds

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.

Source: CNA: redhat

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Red Hat Build of Debezium 3.6 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Quarkus 3.27.5.SP2 Red Hat `netty-codec-http2` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Quarkus 3.33.3.SP2 Red Hat `netty-codec-http2` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat AMQ Broker 7 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat build of Apache Camel 4 for Quarkus 3 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apache Camel for Spring Boot 4 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apicurio Registry 3 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Build of Keycloak Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Data Grid 8 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Fuse 7 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	CNA: redhat
Red Hat JBoss Enterprise Application Platform 7 Red Hat `netty-codec-http2` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unknown	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8 Red Hat `netty-codec-http2` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat JBoss Enterprise Application Platform Expansion Pack Red Hat `netty-codec-http2` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat Single Sign-On 7 Red Hat `netty-codec-http2` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unknown	CNA: redhat

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 5.3 medium	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`	CNA: redhat

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://access.redhat.com/errata/RHSA-2026:69440CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:69470CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:83612CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:95221CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-93492CNA: redhat · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2536895CNA: redhat · issue-tracking, x_refsource_REDHAT

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