Overview
A significant cybersecurity vulnerability has been identified in Cesanta mjs 2.20.0, a popular JavaScript engine for embedded systems. This vulnerability, designated as CVE-2023-49550, allows a remote attacker to cause a denial of service, potentially leading to system compromise or data leakage. Given the widespread use of Cesanta mjs in embedded systems, it is critical to understand this vulnerability and implement appropriate mitigation strategies.
Vulnerability Summary
CVE ID: CVE-2023-49550
Severity: High (CVSS: 7.5)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: A successful exploit may lead to system compromise or data leakage.
Affected Products
Escape the Surveillance Era
Most apps won’t tell you the truth.
They’re part of the problem.
Phone numbers. Emails. Profiles. Logs.
It’s all fuel for surveillance.
Ameeba Chat gives you a way out.
- • No phone number
- • No email
- • No personal info
- • Anonymous aliases
- • End-to-end encrypted
Chat without a trace.
Product | Affected Versions
Cesanta mjs | 2.20.0
How the Exploit Works
The vulnerability resides in the mjs+0x4ec508 component of Cesanta mjs 2.20.0. A remote attacker can exploit this vulnerability by sending specially crafted data to the affected system. Upon successful exploitation, the system enters a denial-of-service state, potentially compromising the system and resulting in data leakage.
Conceptual Example Code
An example of how this vulnerability might be exploited is presented below. This is a simplified representation and may not represent actual exploit code.
POST /mjs+0x4ec508 HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "exploit_data": "specially crafted data" }
In this example, the attacker sends a POST request to the mjs+0x4ec508 endpoint with specially crafted data in the payload. If the exploit is successful, the system would enter a denial-of-service state.
Mitigation Guidance
Users of Cesanta mjs 2.20.0 should apply the vendor-supplied patch to rectify this vulnerability as soon as possible. As a temporary mitigation measure, users may also consider deploying a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and prevent potential exploit attempts.

