CVE-2021-34861 Memory corruption in DAP-2020

High 8.8 Published 25 Oct 2021 Updated 4 Aug 2024

Network-adjacent attackers can execute arbitrary code as root on D-Link DAP-2020 routers via a stack buffer overflow in the webproc endpoint.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-34861?

CVE-2021-34861 is a high-severity memory corruption vulnerability in D-Link DAP-2020, published on 25 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DAP-2020 1.01rc001 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the webproc endpoint, which listens on TCP port 80 by default. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12104.

Weakness: CWE-121

Which versions are affected by CVE-2021-34861?

It affects 1 product.

Products include Dlink Dap-2020 Firmware.

How do I fix CVE-2021-34861?

No fix has been published for CVE-2021-34861 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-34861 being exploited?

There is no known exploitation of CVE-2021-34861 in the wild and no public exploit code.

Sources

Also known as GHSA-3gm8-9xxm-pmhh.