CVE-2026-28369 HIGH

CVE-2026-28369: Undertow: undertow: request smuggling via malformed http request headers

Vendor Red Hat
Product Red Hat JBoss Enterprise Application Platform 8.1
Weakness CWE-444
Published March 27, 2026
Last update June 10, 2026

CVSS base score

8.7/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote attacker to perform request smuggling. Request smuggling allows an attacker to bypass security mechanisms, access restricted information, or manipulate web caches, potentially leading to unauthorized actions or data exposure.

Key dates

02Disclosure timeline

March 27, 2026 CVE published
June 10, 2026 Record updated