VULNERABILITY

FreeBSD: VID-DF126E23-24FA-11F0-AB92-F02F7497ECDA (CVE-2025-43859): h11 accepts some malformed Chunked-Encoding bodies

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FreeBSD: VID-DF126E23-24FA-11F0-AB92-F02F7497ECDA (CVE-2025-43859): h11 accepts some malformed Chunked-Encoding bodies

Severity
10
CVSS
(AV:N/AC:L/Au:N/C:C/I:C/A:C)
Published
04/24/2025
Created
05/02/2025
Added
04/30/2025
Modified
05/01/2025

Description

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.

Solution(s)

  • freebsd-upgrade-package-py310-h11
  • freebsd-upgrade-package-py311-h11
  • freebsd-upgrade-package-py312-h11
  • freebsd-upgrade-package-py39-h11

References

  • CVE-2025-43859

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