CVE-2026-3234

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 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 Software

VendorProductVersion RangeStatus

Weaknesses

  • CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

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.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References