CVE-2023-49550 in MJS
Summary
by MITRE • 01/03/2024
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs+0x4ec508 component.
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Analysis
by VulDB Data Team • 05/16/2025
The vulnerability identified as CVE-2023-49550 affects Cesanta mjs version 2.20.0, a lightweight JavaScript engine designed for embedded systems and IoT devices. This remote denial of service flaw exists within the mjs+0x4ec508 component, which represents a specific memory management or execution path within the JavaScript interpreter. The issue demonstrates a critical weakness in the engine's ability to handle malformed input or specific code patterns that can trigger unexpected behavior in the runtime environment.
The technical flaw manifests when a remote attacker crafts malicious input or JavaScript code that exploits the mjs+0x4ec508 component, leading to a system crash or complete service unavailability. This type of vulnerability falls under the category of improper input validation, where the JavaScript engine fails to properly sanitize or handle edge cases in the code execution flow. The vulnerability is particularly concerning because it can be exploited remotely without requiring authentication or privileged access, making it accessible to any attacker with network connectivity to the affected system.
From an operational impact perspective, this denial of service vulnerability can severely disrupt services that depend on the Cesanta mjs JavaScript engine for embedded applications. The affected systems may include IoT devices, embedded routers, industrial control systems, or any platform that utilizes mjs for scripting functionality. When exploited, the vulnerability can cause complete system shutdowns, requiring manual intervention or system restarts to restore normal operations. This can result in significant downtime, especially in mission-critical environments where continuous operation is essential.
The vulnerability aligns with CWE-400, which addresses improper handling of input that can lead to resource exhaustion or system instability. Additionally, this flaw can be categorized under ATT&CK technique T1499.004, which covers network denial of service attacks. Organizations utilizing Cesanta mjs in production environments should immediately implement mitigations including updating to patched versions of the software, implementing network segmentation to limit exposure, and deploying intrusion detection systems to monitor for exploitation attempts. The remediation process should involve thorough testing of updated software versions to ensure compatibility with existing applications while maintaining security posture against this and similar vulnerabilities.