---
id: CVE-2026-28367
title: A flaw was found in Undertow
summary: >-
  A flaw was found in Undertow. A remote attacker can exploit this vulnerability
  by sending `\r\r\r` as a header block terminator. This can be used for request
  smuggling with certain proxy servers, such as older versions of Apache Traffic
  …
severity: high
cvss: 8.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N'
cwe:
  - CWE-444
vendor: redhat
product: build_of_apache_camel_-_hawtio
affected:
  - build_of_apache_camel_-_hawtio = 4.0
  - build_of_apache_camel_for_spring_boot = 4.0
  - data_grid = 8.0
  - fuse = 7.0.0
  - jboss_enterprise_application_platform = 7.0.0
  - jboss_enterprise_application_platform = 8.0.0
  - jboss_enterprise_application_platform_expansion_pack
  - process_automation = 7.0
  - single_sign-on = 7.0
  - undertow
published: '2026-03-27'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T14:17:15.060'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-28367'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:25125'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:25126'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-28367'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2443260'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28367.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-28367'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-28367'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-03-31T13:27:40.351547Z'
epss: 0.00706
epssPercentile: 0.51954
ingestedAt: '2026-06-29T13:24:34.815Z'
patched:
  - jboss_eap_8_1_for_rhel 8
  - jboss_eap_8_1_for_rhel 9
  - jboss_enterprise_application_platform 8.1.7.GA
---

## Overview

A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\r\r\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

## Affected

- `build_of_apache_camel_-_hawtio = 4.0`
- `build_of_apache_camel_for_spring_boot = 4.0`
- `data_grid = 8.0`
- `fuse = 7.0.0`
- `jboss_enterprise_application_platform = 7.0.0`
- `jboss_enterprise_application_platform = 8.0.0`
- `jboss_enterprise_application_platform_expansion_pack`
- `process_automation = 7.0`
- `single_sign-on = 7.0`
- `undertow`

## Remediation

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

## Vendor advisories

- **RHSA-2026:25125** · Red Hat · fixed in: Red Hat JBoss EAP 8.1 for RHEL 8, Red Hat JBoss EAP 8.1 for RHEL 9 · released 2026-06-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:25125)
- **RHSA-2026:25126** · Red Hat · fixed in: Red Hat JBoss Enterprise Application Platform 8.1.7.GA · released 2026-06-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:25126)
- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, 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 JBoss Enterprise Application Platform Expansion Pack, … · no fix planned: Red Hat Data Grid 8, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Process Automation 7, … · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28367.json)