HTTP Request Smuggling Affecting undertow package, versions *


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-DEBIAN14-UNDERTOW-22106605
  • published31 Oct 2026
  • disclosed30 Oct 2026

Introduced: 30 Oct 2026

NewCVE-2026-91920  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

There is no fixed version for Debian:14 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:14 relevant fixed versions and status.

A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.

CVSS Base Scores

version 3.1