CVE-2021-46054 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::visitRethrow(wasm::Rethrow*).
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Analysis
by VulDB Data Team • 01/13/2022
The vulnerability identified as CVE-2021-46054 represents a critical denial of service weakness within the Binaryen webassembly toolkit version 104. This flaw manifests as an assertion abort during the processing of wasm::WasmBinaryBuilder::visitRethrow operations, which fundamentally disrupts the normal execution flow of the binary compiler. The issue occurs when the WasmBinaryBuilder attempts to handle rethrow operations within webassembly binary format processing, creating a scenario where legitimate input can trigger unexpected program termination.
This vulnerability falls under the category of assertion failure conditions that can be exploited to cause system instability, aligning with CWE-617, which addresses reachable assertions that could be triggered by malicious inputs. The technical implementation involves the wasm::WasmBinaryBuilder class specifically targeting rethrow operations through the visitRethrow method, where an assertion condition fails during processing of malformed or unexpected webassembly binary data structures. The assertion abort mechanism serves as a defensive programming feature that should only trigger under exceptional circumstances, yet in this case it becomes a vector for denial of service attacks.
The operational impact of this vulnerability extends beyond simple program termination, as it can affect any system or application utilizing Binaryen 104 for webassembly binary processing or compilation tasks. Attackers can craft malicious webassembly binaries that specifically trigger this assertion failure, causing the toolchain to crash and preventing legitimate compilation or processing operations from completing successfully. This disruption can cascade into broader system availability issues, particularly in environments where automated build processes or continuous integration pipelines depend on Binaryen for webassembly artifact generation.
From an attack perspective, this vulnerability maps to ATT&CK technique T1499.004, which involves network disruption through resource exhaustion or service interruption. The flaw enables an attacker to consume computational resources and system availability by causing repeated assertion failures that may require manual intervention to resolve. The exploitability of this vulnerability is relatively straightforward as it requires only the ability to provide crafted webassembly input to the affected Binaryen version, making it accessible to attackers with basic knowledge of webassembly binary formats.
Mitigation strategies should focus on immediate version updates to Binaryen 105 or later, where the assertion failure has been addressed and corrected. Organizations should also implement input validation measures that filter or sanitize webassembly binary data before processing through the affected toolchain. Additionally, deployment of runtime monitoring and alerting systems can help detect unusual assertion failures that may indicate exploitation attempts. The remediation process should include thorough testing of updated toolchains to ensure that the fix does not introduce regressions in functionality while maintaining the security improvements that address the underlying assertion abort condition.