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

Product/Component

Brocade Fabric OS

2 more products
Notification Id

36876

Last Updated

26 January 2026

Initial Publication Date

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

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