CRITICALVulnerability
Verified
Global
NVD CRITICAL: CVE-2026-28369 — A flaw was found in Undertow. When Undertow receives an HTTP request where the f...
Friday, March 27, 2026 at 05:16 PM UTC·Source: NIST NVD
Updated: Thursday, April 2, 2026 at 05:46 PM UTC
Executive Summary
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
Analysis
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.
CVSS Score: 8.7. Published: 2026-03-27T17:16:28.240.