CVE-2026-17251 Unauthenticated Denial of Service via Null Pointer Dereference in HTTP Request Parsing
An unauthenticated remote attacker can crash the HTTP service on TP-Link TL-MR6400 v7 routers by sending a malformed session cookie header.
- 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-2026-17251?
CVE-2026-17251 is a high-severity vulnerability in TP-Link Systems Inc. TL-MR6400 v7.0, published on 21 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A NULL pointer dereference vulnerability exists in the HTTP request parsing functionality of TL-MR6400 v7. An unauthenticated remote attacker can trigger the vulnerability by sending a specially crafted HTTP request containing a malformed session cookie header.
Successful exploitation may cause the HTTP service process to crash, resulting in a denial-of-service condition and temporary loss of management or CGI functionality until service recovery.
Weakness: CWE-476
Which versions are affected by CVE-2026-17251?
How do I fix CVE-2026-17251?
No fix has been published for CVE-2026-17251 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-17251 being exploited?
There is no known exploitation of CVE-2026-17251 in the wild and no public exploit code.
Sources
Also known as GHSA-cfmx-mjrq-52xj.