CVE-2026-66749 Let's Chat 0.4.0 - 0.4.8 Denial of Service via Null Dereference in Room Lookup
Authenticated attackers can crash the Let's Chat server by sending a crafted request with a non-existent room ID, causing a null dereference.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66749?
CVE-2026-66749 is a high-severity vulnerability in sdelements lets-chat, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Let's Chat 0.4.0 through 0.4.8 contains a null dereference vulnerability that allows authenticated attackers to crash the server by supplying a valid 24-character hex string room parameter that matches no document in the database. Attackers can send a crafted GET /messages request causing an uncaught TypeError in an asynchronous Mongoose callback that terminates the Node.js server process, with the same defect reachable through multiple code paths including the socket.io interface.
Weakness: CWE-476
Which versions are affected by CVE-2026-66749?
How do I fix CVE-2026-66749?
No fix has been published for CVE-2026-66749 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-66749 being exploited?
There is no known exploitation of CVE-2026-66749 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-qjpw-62vp-8j4q.