Null Dereference Vulnerability in Let's Chat by Theopaid
CVE-2026-66749

7.1HIGH

Key Information:

Vendor

Sdelements

Status
Lets-chat
Vendor
CVE Published:
28 July 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-66749?

A null dereference vulnerability has been identified in versions 0.4.0 through 0.4.8 of Let's Chat. This flaw allows authenticated attackers to crash the server by providing a malformed 24-character hexadecimal string as the room parameter in a GET /messages request. If the specified room does not exist in the database, it triggers an uncaught TypeError in an asynchronous Mongoose callback, resulting in a denial of service that halts the Node.js server process. The vulnerability can be exploited through multiple entry points, including the socket.io interface, making it a significant security concern for users of this chat application.

Affected Version(s)

lets-chat 0.4.0 <= 0.4.8

lets-chat 0.4.0 <= 0.4.8

lets-chat 84981a6d2534445c00ea4e095c934e46943c0b1d <= 617207ff3c0c0bf8e3c7a915bd9ec03f1dd8390c

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-66749 - Proof of Concept

References

https://github.com/theopaid/Unchecked-Room-Lookup-Leads-t...
technical-descriptionexploit
https://www.vulncheck.com/advisories/let-s-chat-denial-of...
third-party-advisory

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Theodosis Paidakis
.