---
id: CVE-2026-3234
title: >-
  Mod_proxy_cluster: mod_proxy_cluster: response body corruption via crlf
  injection
summary: >-
  A flaw was found in  mod_proxy_cluster. This vulnerability, a Carriage Return
  Line Feed (CRLF) injection in the decodeenc() function, allows a remote
  attacker to bypass input validation. By injecting CRLF sequences into the
  cluster confi…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-93
vendor: Red Hat
product: mod_proxy_cluster
affected:
  - mod_proxy_cluster (all versions)
  - mod_proxy_cluster (all versions)
  - jbcs-httpd24-mod_proxy_cluster (all versions)
  - mod_proxy_cluster (all versions)
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-03-12T13:15:10.416041Z'
published: '2026-03-12'
updated: '2026-11-02'
sourceUpdated: '2026-11-02T01:38:38.851Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-3234'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-3234'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2442889'
    label: RHBZ#2442889
tags:
  - cve.org
epss: 0.0033
epssPercentile: 0.263
ingestedAt: '2026-11-05T19:30:42.619Z'
---

## Overview

A flaw was found in  mod_proxy_cluster. This vulnerability, a Carriage Return Line Feed (CRLF) injection in the decodeenc() function, allows a remote attacker to bypass input validation. By injecting CRLF sequences into the cluster configuration, an attacker can corrupt the response body of INFO endpoint responses. Exploitation requires network access to the MCMP protocol port, but no authentication is needed.

## Affected

- `mod_proxy_cluster (all versions)`
- `mod_proxy_cluster (all versions)`
- `jbcs-httpd24-mod_proxy_cluster (all versions)`
- `mod_proxy_cluster (all versions)`

## Remediation

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

### Workarounds

Restrict network access to the MCMP protocol port (typically 6666) for systems running Apache mod_proxy_cluster. Configure firewall rules to limit inbound connections to this port only from trusted internal or management networks. This action reduces the attack surface by preventing unauthorized remote access to the vulnerable service. A service reload or restart may be required for firewall changes to take full effect.