FreeBSD : h11 accepts some malformed Chunked-Encoding bodies (df126e23-24fa-11f0-ab92-f02f7497ecda)

critical Nessus Plugin ID 234953

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the df126e23-24fa-11f0-ab92-f02f7497ecda advisory.

h11 reports:
h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line t erminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issu e 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.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://nvd.nist.gov/vuln/detail/CVE-2025-43859

http://www.nessus.org/u?58d87438

Plugin Details

Severity: Critical

ID: 234953

File Name: freebsd_pkg_df126e2324fa11f0ab92f02f7497ecda.nasl

Version: 1.1

Type: local

Published: 4/29/2025

Updated: 4/29/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

CVSS Score Source: CVE-2025-43859

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:py311-h11, p-cpe:/a:freebsd:freebsd:py310-h11, p-cpe:/a:freebsd:freebsd:py312-h11, cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:py39-h11

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 4/29/2025

Vulnerability Publication Date: 4/24/2025

Reference Information

CVE: CVE-2025-43859