CVE-2021-47854 DD-WRT 45723 - UPNP Buffer Overflow
Remote attackers can execute arbitrary code on DD-WRT routers by sending crafted M-SEARCH packets to the UPNP service.
- 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-2021-47854?
CVE-2021-47854 is a high-severity memory corruption vulnerability in embeDD GmbH DD-WRT, published on 21 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
DD-WRT version 45723 contains a buffer overflow vulnerability in the UPNP network discovery service that allows remote attackers to potentially execute arbitrary code. Attackers can send crafted M-SEARCH packets with oversized UUID payloads to trigger buffer overflow conditions on the target device.
Weakness: CWE-120
Which versions are affected by CVE-2021-47854?
How do I fix CVE-2021-47854?
No fix has been published for CVE-2021-47854 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-2021-47854 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47854 exists.
Sources
Also known as GHSA-fmvf-xj4m-jpwf.