CVE-2021-29324 in OpenSource
Summary
by MITRE • 11/19/2021
OpenSource Moddable v10.5.0 was discovered to contain a stack overflow via the component /moddable/xs/sources/xsScript.c.
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Analysis
by VulDB Data Team • 11/22/2021
The vulnerability CVE-2021-29324 affects the OpenSource Moddable v10.5.0 runtime environment which is designed for embedded systems development and IoT applications. This runtime implements the XS JavaScript engine and provides a platform for developing applications that run on resource-constrained devices. The issue was identified in the xsScript.c component which serves as a core part of the JavaScript execution engine responsible for parsing and executing script code within the Moddable environment.
The technical flaw manifests as a stack overflow condition occurring within the xsScript.c source file when processing certain malformed or excessively complex script inputs. This stack overflow vulnerability arises from inadequate input validation and bounds checking within the script parsing routines. When an attacker can craft malicious JavaScript code that triggers this specific code path, the recursive or iterative processing of the input causes the program stack to exceed its allocated memory limits, resulting in a crash or potentially exploitable behavior. The vulnerability is classified as a classic stack-based buffer overflow that can be triggered through improper handling of script compilation or execution flows.
The operational impact of this vulnerability extends beyond simple application crashes to potentially enable more serious security consequences within the embedded systems environment where Moddable runtime operates. Since Moddable is designed for IoT devices and embedded applications, exploitation of this stack overflow could lead to system instability, denial of service conditions, or in scenarios where additional attack vectors exist, potentially allow for arbitrary code execution. The vulnerability affects systems that process untrusted JavaScript inputs through the Moddable runtime, making it particularly concerning for applications that accept user-generated content or remote script execution capabilities.
Organizations utilizing Moddable v10.5.0 should prioritize immediate mitigation through patching or upgrading to versions that address this stack overflow vulnerability. The fix typically involves implementing proper input validation and bounds checking within the xsScript.c component to prevent excessive stack consumption during script processing. Additionally, deployment strategies should include input sanitization measures and runtime restrictions that limit the complexity and size of scripts executed within the environment. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow and represents a significant concern for the ATT&CK framework under the T1059.007 technique for Scripting, where adversaries may leverage such vulnerabilities to establish persistent access or execute malicious code within constrained device environments.
The root cause of this vulnerability demonstrates poor defensive programming practices in the XS JavaScript engine implementation where adequate stack management and input validation were not properly enforced. Security practitioners should consider implementing runtime monitoring and anomaly detection for stack usage patterns within embedded systems that utilize Moddable runtime environments. Regular security assessments and code reviews focusing on memory management practices within embedded JavaScript engines are essential for preventing similar vulnerabilities from manifesting in production systems. The vulnerability also highlights the importance of thorough testing procedures including fuzzing and boundary condition testing for embedded runtime environments that handle script execution.