CVE-2023-0836

Publication date 27 March 2023

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An information leak vulnerability was discovered in HAProxy 2.1, 2.2 before 2.2.27, 2.3, 2.4 before 2.4.21, 2.5 before 2.5.11, 2.6 before 2.6.8, 2.7 before 2.7.1. There are 5 bytes left uninitialized in the connection buffer when encoding the FCGI_BEGIN_REQUEST record. Sensitive data may be disclosed to configured FastCGI backends in an unexpected way.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
haproxy	23.04 lunar	Not affected
	22.10 kinetic	Fixed 2.4.18-1ubuntu1.3
	22.04 LTS jammy	Fixed 2.4.18-0ubuntu1.3
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Ignored end of standard support

Patch details

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

Package	Patch details
haproxy	Upstream: https://git.haproxy.org/?p=haproxy.git;a=commit;h=2e6bf0a2722866ae0128a4392fa2375bd1f03ff8 Upstream: https://git.haproxy.org/?p=haproxy-2.6.git;a=commit;h=f988992d16f45ef03d5bbb024a1042ed8123e4c5 Upstream: https://git.haproxy.org/?p=haproxy-2.2.git;a=commit;h=18575ba4e5057afdb80cc06135272889ae1fa2d1

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.5 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	None
Availability impact	None

Scores

Parameter	Value
Base score	7.5 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-5994-1
HAProxy vulnerability
3 April 2023

Other references

https://www.cve.org/CVERecord?id=CVE-2023-0836