HTTP Request Smuggling Affecting undertow package, versions *


Severity

Recommended
0.0
critical
0
10

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Threat Intelligence

EPSS
0.68% (48th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-UNDERTOW-15805893
  • published29 Mar 2026
  • disclosed27 Mar 2026

Introduced: 27 Mar 2026

CVE-2026-28369  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable undertow.

NVD Description

Note: Versions mentioned in the description apply only to the upstream undertow package and not the undertow package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 Base Scores

version 3.1