CVE-2019-7154 in Binaryen
Summary
by MITRE
The main function in tools/wasm2js.cpp in Binaryen 1.38.22 has a heap-based buffer overflow because Emscripten is misused, triggering an error in cashew::JSPrinter::printAst() in emscripten-optimizer/simple_ast.h. A crafted input can cause segmentation faults, leading to denial-of-service, as demonstrated by wasm2js.
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Analysis
by VulDB Data Team • 07/03/2023
The vulnerability identified as CVE-2019-7154 resides within the Binaryen toolchain version 1.38.22, specifically in the tools/wasm2js.cpp file where the main function exhibits heap-based buffer overflow behavior. This flaw manifests through improper handling of Emscripten integration within the wasm2js conversion process, creating a critical security risk that can be exploited through carefully crafted input files. The root cause stems from the misutilization of Emscripten's optimization capabilities, which triggers an error condition within the cashew::JSPrinter::printAst() function located in emscripten-optimizer/simple_ast.h, demonstrating how seemingly innocuous toolchain interactions can create devastating memory corruption vulnerabilities.
The technical implementation of this vulnerability exploits the interaction between Binaryen's WebAssembly to JavaScript compilation process and Emscripten's optimization framework. When processing maliciously constructed WebAssembly files, the wasm2js tool fails to properly validate input parameters before passing them to the Emscripten optimizer, resulting in a buffer overflow condition that corrupts heap memory. This overflow specifically occurs during the Abstract Syntax Tree (AST) printing phase where the cashew::JSPrinter attempts to serialize the parsed WebAssembly structure into JavaScript code. The flaw represents a classic heap buffer overflow scenario where insufficient bounds checking allows arbitrary data to overwrite adjacent memory regions, potentially leading to unpredictable program behavior.
The operational impact of CVE-2019-7154 extends beyond simple denial-of-service conditions, as the heap corruption can potentially be leveraged for more sophisticated attacks depending on the execution environment. When exploited, this vulnerability can cause segmentation faults that crash the wasm2js conversion tool, effectively preventing legitimate WebAssembly to JavaScript compilation operations from completing successfully. The vulnerability affects developers and systems that rely on Binaryen's wasm2js functionality for WebAssembly processing, particularly in environments where automated compilation pipelines process untrusted input. This creates significant operational risks for continuous integration systems, web application frameworks, and development toolchains that depend on the affected toolchain components.
Mitigation strategies for CVE-2019-7154 should prioritize immediate patching of Binaryen to version 1.38.23 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should implement input validation measures that prevent malformed WebAssembly files from reaching the wasm2js conversion process, utilizing sandboxing techniques to isolate the toolchain execution environment. Additionally, monitoring systems should be deployed to detect unusual patterns in wasm2js usage that might indicate attempted exploitation. From a cybersecurity perspective, this vulnerability aligns with CWE-121 heap-based buffer overflow weakness and can be categorized under ATT&CK technique T1059.007 for application execution through script interpreters, emphasizing the need for proper input sanitization and memory safety practices in toolchain development. The vulnerability also demonstrates the importance of secure coding practices in build systems and compilation tools, as these components often operate with elevated privileges and can serve as attack vectors for broader system compromise.