CVE-2025-12543

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.

Scoring

Severity
CRITICAL
CVSS base score
9.6
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
EPSS probability
1.35%
CWE
CWE-20
Published
2026-01-07
Last modified
2026-09-07

Affected products

Weakness type

Related vulnerabilities

Markdown version · Browse all CVEs