CVE-2021-39242

haproxy: it can lead to a situation with an attacker-controlled HTTP Host header because a mismatch between Host and authority is mishandled

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3. It can lead to a situation with an attacker-controlled HTTP Host header, because a mismatch between Host and authority is mishandled.

Se ha detectado un problema en HAProxy versiones 2.2 anteriores a 2.2.16, versiones 2.3 anteriores a 2.3.13 y versiones 2.4 anteriores a 2.4.3. Puede conllevar a una situación con un encabezado HTTP Host controlada por un atacante, porque es manejado inapropiadamente un desajuste entre Host y autoridad.

haproxy was found to be vulnerable to HTTP host header attack: This problem creates a scenario in which it's possible to drop the Host header and use the authority only after forwarding to a
second http2 layer, possibly causing two differing values of Host at a different stage. The highest threat from this vulnerability is data integrity.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-08-17 CVE Reserved
2021-08-17 CVE Published
2024-08-04 CVE Updated
2024-10-18 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-20: Improper Input Validation
CWE-755: Improper Handling of Exceptional Conditions

CAPEC

References (7)

URL	Tag	Source
https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=b5d2b9e154d78e4075db163826c5e0f6d31b2ab1	X_refsource_misc
https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html	X_refsource_misc

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM	2023-11-07
https://www.debian.org/security/2021/dsa-4960	2023-11-07
https://access.redhat.com/security/cve/CVE-2021-39242	2022-01-05
https://bugzilla.redhat.com/show_bug.cgi?id=1995112	2022-01-05

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Haproxy Search vendor "Haproxy"		Haproxy Search vendor "Haproxy" for product "Haproxy"				>= 2.2.0 < 2.2.16 Search vendor "Haproxy" for product "Haproxy" and version " >= 2.2.0 < 2.2.16"		-		Affected
Haproxy Search vendor "Haproxy"		Haproxy Search vendor "Haproxy" for product "Haproxy"				>= 2.3.0 < 2.3.13 Search vendor "Haproxy" for product "Haproxy" and version " >= 2.3.0 < 2.3.13"		-		Affected
Haproxy Search vendor "Haproxy"		Haproxy Search vendor "Haproxy" for product "Haproxy"				>= 2.4.0 < 2.4.3 Search vendor "Haproxy" for product "Haproxy" and version " >= 2.4.0 < 2.4.3"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				11.0 Search vendor "Debian" for product "Debian Linux" and version "11.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected