# CVE-2026-93492: Io.netty/netty-codec-http2: netty: http/2 hpackencoder dos with large table size

Status: published. Published: 2026-09-18. Updated: 2026-11-04.

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

- 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

- Red Hat / Red Hat Build of Debezium 3.6 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Quarkus 3.27.5.SP2 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Quarkus 3.33.3.SP2 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform 8.1 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat AMQ Broker 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apache Camel 4 for Quarkus 3 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apache Camel for Spring Boot 4 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat build of Apicurio Registry 3 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Build of Keycloak (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Data Grid 8 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Fuse 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform 8 (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat JBoss Enterprise Application Platform Expansion Pack (netty-codec-http2): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Single Sign-On 7 (netty-codec-http2): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.37% as of 2026-11-04; percentile 31.22%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-1035

## Exploit evidence

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

## References

- https://access.redhat.com/errata/RHSA-2026:69440 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:69470 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:83612 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:95221 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-93492 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2536895 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-93492; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93492; retrieved 2026-11-04; source updated Not reported

Revision: a0f1056e62284d9cd24e53051e6ae03290f2cb5b0a7267df75b704ce117c755b

Canonical: https://y2.dev/cve/CVE-2026-93492

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