HTTP Request Smuggling Affecting localstack package, versions <4.3.0-r1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.04% (13th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LOCALSTACK-9892420
  • published28 Apr 2025
  • disclosed24 Apr 2025

Introduced: 24 Apr 2025

CVE-2025-43859  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade Chainguard localstack to version 4.3.0-r1 or higher.

NVD Description

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

h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.

CVSS Base Scores

version 3.1