CVE-2026-28369

Severity
9.1CRITICAL
EPSS
0.1%
top 64.73%
CISA KEV
Not in KEV
Exploit
No known exploits
Timeline
PublishedMar 27

Description

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 vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:NExploitability: 2.2 | Impact: 5.8

Affected Packages8 packages

Also affects: Enterprise Linux 9.0

🔴Vulnerability Details

4
OSV
CVE-2026-28369: A flaw was found in Undertow2026-03-27
CVEList
Undertow: undertow: request smuggling via malformed http request headers2026-03-27
OSV
Undertow is Vulnerable to HTTP Request/Response Smuggling2026-03-27
GHSA
Undertow is Vulnerable to HTTP Request/Response Smuggling2026-03-27

📋Vendor Advisories

2
Debian
CVE-2026-28369: undertow - A flaw was found in Undertow. When Undertow receives an HTTP request where the f...2026
Red Hat
undertow: Undertow: Request Smuggling via Malformed HTTP Request Headers2025-08-27

🕵️Threat Intelligence

1
Wiz
CVE-2026-28369 Impact, Exploitability, and Mitigation Steps | Wiz