CVE-2021-46048 in Binaryen
Summary
by MITRE • 01/10/2022
A Denial of Service vulnerability exists in Binaryen 104 due to an assertion abort in wasm::WasmBinaryBuilder::readFunctions.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/13/2022
The vulnerability identified as CVE-2021-46048 represents a critical denial of service weakness within the Binaryen webassembly toolchain version 104. This issue manifests as an assertion abort during the processing of webassembly binary format files, specifically within the wasm::WasmBinaryBuilder::readFunctions component. The flaw occurs when the binary builder encounters malformed or specially crafted webassembly binary inputs that trigger an internal assertion failure, causing the entire processing pipeline to terminate abruptly.
The technical root cause of this vulnerability lies in insufficient input validation within the webassembly binary parsing logic. When the wasm::WasmBinaryBuilder::readFunctions method processes webassembly binary data, it fails to properly handle edge cases or malformed input sequences that would normally be gracefully rejected or parsed with appropriate error handling. This assertion failure represents a classic lack of defensive programming practices where the code assumes certain input conditions will always be met without proper validation. The vulnerability maps to CWE-617, which describes reachable assertions that can be triggered by crafted inputs, and specifically aligns with CWE-119, concerning weaknesses that allow for memory access violations through improper input handling.
The operational impact of this vulnerability extends beyond simple service disruption to potentially affect automated build systems, continuous integration pipelines, and webassembly processing applications that rely on Binaryen for binary format conversion or validation. An attacker could exploit this weakness by providing a maliciously crafted webassembly binary file that triggers the assertion abort, causing the processing application to crash and terminate unexpectedly. This could result in denial of service for legitimate users attempting to process valid webassembly files, as the system may become unresponsive or require manual restart to recover from the crash state. The vulnerability is particularly concerning in environments where automatic processing of user-uploaded webassembly content occurs, as it provides a straightforward path to service disruption.
Mitigation strategies for CVE-2021-46048 should prioritize immediate patching of affected Binaryen versions to 105 or later, where the assertion handling has been corrected. Organizations should implement input validation measures that sanitize webassembly binary inputs before processing, including size limitations and format verification checks. Additionally, deployment of intrusion detection systems that monitor for unusual process termination patterns or assertion failures can help detect exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1499.004, which covers network denial of service attacks, and T1595.001, concerning network scanning and enumeration techniques that may be used to identify vulnerable systems. Implementing proper error handling and graceful degradation mechanisms within webassembly processing applications can also reduce the impact of such vulnerabilities by preventing complete system crashes when malformed inputs are encountered.