CVE-2023-43622

Publication date 23 October 2023

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

7.5 · High

Score breakdown

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Read the notes from the security team

Why is this CVE low priority?

Apache developers consider this to be a low-impact issue

Learn more about Ubuntu priority

Status

Package Ubuntu Release Status
apache2 23.10 mantic
Fixed 2.4.57-2ubuntu2.1
23.04 lunar
Fixed 2.4.55-1ubuntu2.1
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected

Notes

mdeslaur

backporting this to jammy and earlier will likely require backporting the whole 2.0.10 version of the http/2 module as it refactors how connections and streams are handled: https://github.com/apache/httpd/commit/9767274b884a110e9244f59f50bd31ff1cae2933

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
apache2

Severity score breakdown

Parameter Value
Base score 7.5 · High
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H