CVE-2025-5623 D-Link DIR-816 qosClassifier stack-based overflow

Critical 9.3 Published 5 Jun 2025 Updated 5 Jun 2025

Remote attackers can exploit a stack-based buffer overflow in the qosClassifier function of unsupported D-Link DIR-816 routers to execute arbitrary code.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-5623?

CVE-2025-5623 is a critical memory corruption vulnerability in Dlink Dir-816 Firmware, published on 5 Jun 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability was found in D-Link DIR-816 1.10CNB05. It has been classified as critical. This affects the function qosClassifier of the file /goform/qosClassifier. The manipulation of the argument dip_address/sip_address leads to stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. This vulnerability only affects products that are no longer supported by the maintainer.

Weakness: CWE-121, CWE-787, CWE-119

Which versions are affected by CVE-2025-5623?

It affects 1 product.

Products include Dlink Dir-816 Firmware.

How do I fix CVE-2025-5623?

No fix has been published for CVE-2025-5623 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-2025-5623 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-5623 exists.

All Dlink Dir-816 Firmware vulnerabilities

Sources

Also known as GHSA-v8p3-7jrm-c3rr.