CVE-2021-44224

Publication date 20 December 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A crafted URI sent to httpd configured as a forward proxy (ProxyRequests on) can cause a crash (NULL pointer dereference) or, for configurations mixing forward and reverse proxy declarations, can allow for requests to be directed to a declared Unix Domain Socket endpoint (Server Side Request Forgery). This issue affects Apache HTTP Server 2.4.7 up to 2.4.51 (included).

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
apache2	22.04 LTS jammy	Fixed 2.4.52-1ubuntu1
	21.10 impish	Fixed 2.4.48-3.1ubuntu3.2
	21.04 hirsute	Fixed 2.4.46-4ubuntu1.5
	20.04 LTS focal	Fixed 2.4.41-4ubuntu3.9
	18.04 LTS bionic	Fixed 2.4.29-1ubuntu4.21
	16.04 LTS xenial	Fixed 2.4.18-2ubuntu3.17+esm4
	14.04 LTS trusty	Fixed 2.4.7-1ubuntu4.22+esm3

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Notes

mdeslaur

fixed by r1895955+r1896044 in 2.4.x

Patch details

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

Package	Patch details
apache2	Upstream: https://svn.apache.org/viewvc?view=revision&revision=1895955 Upstream: https://svn.apache.org/viewvc?view=revision&revision=1896044 Upstream: a962ba7 Upstream: a0521d2

Severity score breakdown

Parameter	Value
Base score	8.2 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	Low
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H