Integer Overflow Vulnerability in HAProxy Versions 2.0 to 2.5
CVE-2021-40346

7.5HIGH

Key Information:

Vendor

Haproxy

Status
Haproxy
Vendor
CVE Published:
8 September 2021

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 92%

What is CVE-2021-40346?

An integer overflow vulnerability is present in HAProxy versions 2.0 through 2.5. This flaw is associated with the htx_add_header function, enabling attackers to exploit the vulnerability to conduct an HTTP request smuggling attack. By bypassing all configured HTTP request Access Control Lists (ACLs) in HAProxy, the attacker may gain unauthorized access or manipulate HTTP requests, posing significant risks to web application security.

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2021-40346
Created by knqyf263

CVE-2021-40346-POC
Created by donky16

HAProxy_CVE-2021-40346
Created by Vulnmachines

References

https://www.mail-archive.com/haproxy%40formilux.org
x_refsource_MISC
https://git.haproxy.org/?p=haproxy.git
x_refsource_MISC
https://www.debian.org/security/2021/dsa-4968
vendor-advisoryx_refsource_DEBIAN

EPSS Score

92% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.