VULNERABILITY INTELLIGENCE

CVE-2025-12543

CVSS score9.6 CRITICAL
EPSS probability1.33%
CISA KEVNot currently listed
Published2026-01-07
Last modified2026-10-14
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

Description

A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.

Weakness classification

  • secalert@redhat.com: CWE-20
  • 0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-20

Primary references