CVE-2021-45293 in Binaryen
Summary
by MITRE • 12/21/2021
A Denial of Service vulnerability exists in Binaryen 103 due to an Invalid memory address dereference in wasm::WasmBinaryBuilder::visitLet.
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Analysis
by VulDB Data Team • 12/25/2021
The vulnerability identified as CVE-2021-45293 represents a critical denial of service weakness within the Binaryen webassembly toolkit version 103. This issue manifests as an invalid memory address dereference during the processing of webassembly binary format files, specifically within the wasm::WasmBinaryBuilder::visitLet function. The flaw occurs when the binary builder attempts to parse and construct webassembly modules, creating a scenario where maliciously crafted input can trigger unexpected program termination or system instability.
This vulnerability falls under the category of memory safety issues and can be classified as CWE-476_NULL_POINTER_DEREFERENCE, representing a fundamental flaw in how the software handles memory references during parsing operations. The affected component wasm::WasmBinaryBuilder::visitLet operates as part of the webassembly binary parsing pipeline, where it processes let constructs within webassembly modules. When encountering malformed or specially crafted input, the function fails to properly validate memory access patterns, leading to a crash condition that prevents normal operation of the binaryen toolchain.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the entire webassembly compilation and processing pipeline. Attackers can exploit this weakness by providing malicious webassembly binary files that trigger the invalid memory dereference, causing the application to crash or become unresponsive. This makes the vulnerability particularly dangerous in environments where binaryen is used for automated processing of webassembly modules, such as in continuous integration systems, webassembly compilers, or server-side processing environments. The denial of service condition can be leveraged to disrupt legitimate operations and potentially create opportunities for further exploitation.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1499.004 Disruption of Service, specifically targeting availability through denial of service conditions. The exploitability of CVE-2021-45293 is relatively straightforward as it requires only the ability to feed malformed webassembly input to the vulnerable binaryen component. This makes it particularly concerning for automated systems that process untrusted webassembly content, including web browsers, webassembly runtime environments, or any system that relies on binaryen for webassembly processing. The vulnerability demonstrates poor input validation and memory management practices within the webassembly binary parsing infrastructure, highlighting the need for robust error handling and defensive programming techniques in security-critical components.
The recommended mitigations for CVE-2021-45293 include immediate upgrade to Binaryen version 104 or later, which contains the necessary patches to address the memory dereference issue. Organizations should also implement input validation measures when processing webassembly files, including sanitization of input data and implementation of proper error handling routines. Additionally, deployment of intrusion detection systems and monitoring for unusual process termination patterns can help detect exploitation attempts. The fix typically involves strengthening the memory access validation within the visitLet function to ensure proper bounds checking and null pointer validation before any memory operations occur, thereby preventing the invalid address dereference condition that leads to the denial of service scenario.