Undertow-core: undertow http server fails to reject malformed host headers leading to potential cache poisoning and ssrf (CVE-2025-12543)
36876
26 January 2026
26 January 2026
CLOSED
LOW
9.6:CRITICAL -- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
CVE-2025-12543
|
Brocade Security Advisory ID |
BSA-2026-3333 |
|
Component |
Wildfly |
|
|
|
Summary
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.
Products Confirmed Not Affected
- Brocade ASCG: [VEX Justification: Component_not_present]
- Brocade Fabric OS: [VEX Justification: Component_not_present]
- Brocade SANnav: [VEX Justification: Component_not_present]
Revision History
|
Version |
Change |
Date |
|
1.0 |
Initial Publication |
1/26/2026 |
Disclaimer
THIS DOCUMENT IS PROVIDED ON AN AS-IS BASIS SOLELY FOR INFORMATIONAL PURPOSES AND DOES NOT IMPLY ANY KIND OF GUARANTY OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. YOUR USE OF THE INFORMATION CONTAINED HEREIN IS AT YOUR OWN RISK. ALL INFORMATION PROVIDED HEREIN IS BASED ON BROCADE'S CURRENT KNOWLEDGE AND UNDERSTANDING OF THE VULNERABILITY AND IMPACT TO BROCADE HARDWARE AND SOFTWARE PRODUCTS. BROCADE RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.