CVE-2020-36214 in multiqueue2 Crate
Summary
by MITRE • 01/26/2021
An issue was discovered in the multiqueue2 crate before 0.1.7 for Rust. Because a non-Send type can be sent to a different thread, a data race can occur.
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Analysis
by VulDB Data Team • 02/20/2021
The vulnerability identified as CVE-2020-36214 resides within the multiqueue2 crate version 0.1.6 and earlier, representing a critical concurrency flaw that undermines Rust's memory safety guarantees. This issue specifically targets the crate's handling of type safety across thread boundaries, where the implementation fails to properly enforce Rust's Send trait requirements. The multiqueue2 crate is designed to facilitate multi-threaded queue operations, but the flaw allows for improper type transmission between threads, creating a dangerous scenario where non-Send types are erroneously moved across execution contexts. Such behavior directly violates Rust's fundamental concurrency model and can lead to undefined behavior during program execution.
The technical root cause of this vulnerability stems from inadequate type checking within the crate's thread communication mechanisms. When a type that does not implement the Send trait is passed to another thread, the runtime environment should prevent such operations to maintain memory safety. However, the multiqueue2 implementation permits this transmission, creating a data race condition where multiple threads may simultaneously access shared data without proper synchronization. This flaw specifically manifests when the crate's internal queue management system attempts to move ownership of non-Send types between threads, bypassing Rust's compile-time safety checks. The vulnerability is categorized under CWE-362, which describes a concurrent execution using shared data without proper synchronization, and aligns with ATT&CK technique T1059.007 for process injection and T1070.006 for indicator removal, as it can enable malicious code execution through race condition exploitation.
The operational impact of this vulnerability extends beyond simple data corruption, potentially enabling attackers to execute arbitrary code or cause system instability. When non-Send types are transmitted between threads, the program's memory layout becomes unpredictable, allowing for potential memory corruption that could be exploited to gain unauthorized access or escalate privileges. The data race condition creates opportunities for attackers to manipulate shared resources, potentially leading to information disclosure or denial of service conditions. In multi-threaded applications using this crate, the vulnerability could result in crashes, data loss, or unauthorized code execution, particularly when applications rely on complex concurrent data structures. The issue affects any Rust application that utilizes the multiqueue2 crate for managing multi-threaded queue operations, making it particularly dangerous in environments where concurrent processing is essential for application functionality.
Mitigation strategies for CVE-2020-36214 require immediate action to upgrade to version 0.1.7 or later of the multiqueue2 crate, which contains the necessary fixes to properly enforce Send trait requirements. System administrators and developers should conduct comprehensive code reviews to identify any other instances where similar concurrency patterns might exist within their applications. The fix implemented in version 0.1.7 addresses the core issue by ensuring that only types implementing the Send trait can be safely transmitted between threads, thereby preventing the data race conditions that previously occurred. Additionally, developers should implement proper synchronization mechanisms such as mutexes or channels when sharing data between threads, and consider using Rust's built-in concurrency primitives to ensure type safety. Organizations should also implement continuous monitoring for similar vulnerabilities in their dependency chains, as this type of concurrency flaw can potentially exist in other crates that handle inter-thread communication, making regular security audits of third-party dependencies essential for maintaining system integrity.