CVE-2020-23309 in JerryScript
Summary
by MITRE • 06/11/2021
There is an Assertion 'context_p->stack_depth == context_p->context_stack_depth' failed at js-parser-statm.c:2756 in parser_parse_statements in JerryScript 2.2.0.
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Analysis
by VulDB Data Team • 09/11/2025
This vulnerability exists within the JerryScript JavaScript engine version 2.2.0 and represents a critical assertion failure that occurs during the parsing phase of JavaScript code execution. The assertion failure manifests at line 2756 in the js-parser-statm.c source file where the engine attempts to validate the relationship between context_p->stack_depth and context_p->context_stack_depth. This particular assertion failure indicates a potential mismatch in the internal stack management mechanisms that JerryScript employs to track execution context and stack frames during JavaScript parsing operations.
The technical flaw stems from improper stack depth validation within the parser component of JerryScript, specifically when processing certain JavaScript statements. When the parser encounters malformed or specially crafted JavaScript code, it can cause the stack depth variables to become inconsistent, leading to the assertion failure that terminates the execution process. This type of vulnerability falls under the category of assertion failure conditions that can be exploited to cause denial of service attacks or potentially lead to more severe consequences depending on the execution environment. The vulnerability represents a classic example of improper state management in parsing components, which can be categorized under CWE-617, which deals with reachable assertions that can be exploited to cause program termination or unexpected behavior.
The operational impact of this vulnerability is significant for systems that rely on JerryScript for JavaScript execution, particularly in embedded environments or IoT devices where resource constraints make such failures more critical. An attacker who can influence the JavaScript code being parsed by JerryScript could potentially trigger this assertion failure, resulting in application crashes or denial of service conditions that could affect the availability of services. The vulnerability demonstrates how seemingly minor inconsistencies in stack management can have substantial operational consequences in embedded scripting environments where stability and reliability are paramount.
Mitigation strategies for this vulnerability should focus on upgrading to a patched version of JerryScript where the assertion failure has been addressed through proper stack depth validation and management. System administrators should also implement input validation measures to prevent untrusted JavaScript code from being executed within environments that use JerryScript. Additionally, monitoring and logging of parsing operations can help detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or cause system instability. Organizations should also consider implementing sandboxing mechanisms and runtime protections to limit the impact of such vulnerabilities in production environments. The fix typically involves correcting the stack depth tracking logic to ensure proper synchronization between the parser's internal state variables and the actual execution context being processed.