---
id: CVE-2026-93491
title: A flaw was found in Netty's HttpServerCodec
summary: >-
  A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated
  attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a
  single connection and withholding reads. This action causes the
  methodOverflowQueue to gr…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
vendor: Red Hat
product: netty-codec-http
affected:
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
  - netty-codec-http
  - netty-codec-http
  - netty-codec-http (all versions)
  - netty-codec-http (all versions)
published: '2026-09-18'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T19:16:57.913'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93491'
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/errata/RHSA-2026:70257'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93491'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536891'
    label: secalert@redhat.com
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.1.138.Final'
    label: secalert@redhat.com
  - url: 'https://github.com/netty/netty/releases/tag/netty-4.2.18.Final'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93491.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93491'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93491'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T19:06:39.794513Z'
epss: 0.00867
epssPercentile: 0.5694
ingestedAt: '2026-09-18T13:41:41.659Z'
---

## Overview

A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a single connection and withholding reads. This action causes the methodOverflowQueue to grow without limit, leading to unbounded heap memory consumption and a denial of service due to memory exhaustion.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat AMQ Broker 7, Red Hat AMQ Clients, 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, … · no fix planned: Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7, Red Hat AMQ Broker 7, … · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93491.json)