Vulnerability Report

CVE-2026-28369

Title: Undertow Request Smuggling via leading spaces in HTTP header

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-28369.

CWE Category CWE-444

Published Date Mar 27, 2026

Modified Date Oct 14, 2026

Exploit Status Not Found

Score 8.7 CVSS v3.1

Exploit Probability (EPSS)

0.89%

Vulnerability Summary

CVE-2026-28369: 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.

Impacted Vendors

Reference Links

https://access.redhat.com/security/cve/CVE-2026-28369 https://bugzilla.redhat.com/show_bug.cgi?id=2443262

CVSS v3.1

Source Entity [email protected]

Severity HIGH

8.7

Attack Vector

NETWORK

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

CHANGED

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