CVE-2025-43859

Publication date 24 April 2025

Last updated 30 May 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.1 · Critical

Score breakdown

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.

Status

Package Ubuntu Release Status
python-h11 25.04 plucky
Fixed 0.14.0-1ubuntu0.25.04.1
24.10 oracular
Fixed 0.14.0-1ubuntu0.24.10.1
24.04 LTS noble
Fixed 0.14.0-1ubuntu0.24.04.1
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected

Severity score breakdown

Parameter Value
Base score 9.1 · Critical
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact None
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N