---
id: CVE-2026-93492
title: A flaw was found in Netty's HTTP/2 HpackEncoder
summary: >-
  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, l…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-1035
vendor: Red Hat
product: netty-codec-http2
affected:
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2 (all versions)
  - netty-codec-http2
  - netty-codec-http2
  - netty-codec-http2 (all versions)
  - netty-codec-http2
published: '2026-09-18'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T10:17:38.287'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93492'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:69440'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:69470'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93492'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536895'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93492.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93492'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93492'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T14:40:19.700669Z'
epss: 0.00644
epssPercentile: 0.4871
ingestedAt: '2026-09-18T13:41:41.659Z'
---

## Overview

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

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: 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, … · no fix planned: Red Hat build of Apicurio Registry 3, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7, … · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93492.json)