CVE-2025-12543 CRITICAL

CVE-2025-12543: Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf

Vendor Red Hat
Product Red Hat build of Apache Camel 4.14.4 for Spring Boot 3.5.11
Weakness CWE-20 · Input validation
Published January 7, 2026
Last update June 30, 2026
View on NVD All CVEs

CVSS base score

9.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

January 7, 2026 CVE published
June 30, 2026 Record updated