CVE-2021-46491 in Jsish
Summary
by MITRE • 01/28/2022
Jsish v3.5.0 was discovered to contain a SEGV vulnerability via Jsi_CommandPkgOpts at src/jsiCmds.c. This vulnerability can lead to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 01/30/2022
The vulnerability identified as CVE-2021-46491 affects Jsish version 3.5.0, a JavaScript interpreter implementation that provides both command line and embedded scripting capabilities. This security flaw manifests as a segmentation fault within the Jsi_CommandPkgOpts function located in the src/jsiCmds.c source file. The issue represents a critical stability concern that can be exploited to disrupt service availability through controlled input manipulation. The Jsish interpreter is commonly used in embedded systems and server environments where reliable operation is essential for maintaining system integrity and user access. When this vulnerability is triggered, the application crashes due to improper memory management during command package option processing, leading to an unhandled segmentation violation that terminates the interpreter process.
The technical root cause of this vulnerability stems from inadequate input validation and memory handling within the command package options processing mechanism. Specifically, the Jsi_CommandPkgOpts function fails to properly validate or sanitize input parameters before attempting to process them, resulting in memory access violations when malformed or unexpected data structures are encountered. This type of flaw aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The vulnerability can be exploited through carefully crafted inputs that manipulate the command package option parsing logic, potentially allowing attackers to cause the interpreter to crash repeatedly. The segmentation fault occurs during the execution phase when the interpreter attempts to access memory locations that are either unmapped or protected, causing the operating system to terminate the process abruptly.
The operational impact of CVE-2021-46491 extends beyond simple service disruption to encompass broader system reliability concerns. In environments where Jsish serves as a critical component for automation scripts, embedded applications, or server-side processing, this vulnerability can result in significant downtime and service unavailability. Attackers can leverage this DoS condition to repeatedly crash the interpreter, effectively denying legitimate users access to the scripting functionality. The vulnerability is particularly concerning in automated deployment scenarios or continuous integration pipelines where Jsish is used for configuration management or script execution. Organizations utilizing this interpreter in production environments may experience cascading failures if dependent services rely on its stability, potentially affecting multiple system components that depend on the interpreter's functionality.
Mitigation strategies for this vulnerability should prioritize immediate patching of the Jsish interpreter to version 3.5.1 or later, which contains the necessary code modifications to address the memory handling issues. System administrators should implement monitoring solutions to detect unusual crash patterns that may indicate exploitation attempts, while also establishing robust process restart mechanisms to minimize service downtime. Input validation should be enhanced at multiple levels to prevent malformed data from reaching the vulnerable function, including implementing proper parameter sanitization and bounds checking. Security teams should consider implementing network-level controls to restrict access to Jsish interfaces when possible, and maintain detailed logging of all interpreter usage to facilitate forensic analysis if exploitation occurs. The vulnerability demonstrates the importance of proper memory management in interpreted languages and underscores the need for comprehensive testing including fuzzing and memory analysis to identify similar issues in other components of the system. Organizations should also review their incident response procedures to ensure rapid containment and recovery from DoS attacks targeting interpreter components, as outlined in the attack patterns documented in the MITRE ATT&CK framework under the execution and privilege escalation domains.