Is CVE-2021-43437 actively exploited?

No active exploitation of CVE-2021-43437 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-43437 be exploited remotely?

Yes. CVE-2021-43437 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-43437?

CVE-2021-43437 has a CVSS score of 8.8 (HIGH).

HOME VULNERABILITIESCVE-2021-43437

HIGH

CVE-2021-43437

CWE-74Published: December 20, 2021· Updated: Jun 17, 2026

8.8

CVSS v3.1

Official Description

In sourcecodetester Engineers Online Portal as of 10-21-21, an attacker can manipulate the Host header as seen by the web application and cause the application to behave in unexpected ways. Very often multiple websites are hosted on the same IP address. This is where the Host Header comes in. This header specifies which website should process the HTTP request. The web server uses the value of this header to dispatch the request to the specified website. Each website hosted on the same IP address is called a virtual host. And It's possible to send requests with arbitrary Host Headers to the first virtual host.

NVD Source

Technical Analysis

CVE-2021-43437 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.