CVE-2020-36211 in gfwx Crate
Summary
by MITRE • 01/26/2021
An issue was discovered in the gfwx crate before 0.3.0 for Rust. Because ImageChunkMut does not have bounds on its Send trait or Sync trait, a data race and memory corruption can occur.
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Analysis
by VulDB Data Team • 02/20/2021
The vulnerability identified as CVE-2020-36211 resides within the gfwx crate version 0.3.0 and earlier, representing a critical concurrency flaw that undermines memory safety mechanisms in Rust applications. This issue specifically targets the ImageChunkMut type which lacks proper bounds on its Send and Sync traits, creating an avenue for undefined behavior through data races and subsequent memory corruption. The flaw demonstrates a fundamental misunderstanding of Rust's ownership model and concurrency guarantees, where the absence of proper trait bounds allows potentially unsafe concurrent access to mutable data structures.
The technical root cause stems from the improper implementation of Send and Sync trait bounds for the ImageChunkMut type within the gfwx crate. In Rust's type system, Send indicates that a type can be safely transferred between threads, while Sync indicates that a type can be safely shared between threads. When these traits are not properly constrained, the compiler cannot guarantee memory safety during concurrent operations. This particular vulnerability manifests when multiple threads attempt to access or modify the same ImageChunkMut instance simultaneously, leading to data races that can result in memory corruption. The absence of bounds on these traits effectively removes the compile-time safety checks that would normally prevent such unsafe operations, creating a scenario where the runtime behavior becomes unpredictable and potentially exploitable.
The operational impact of this vulnerability extends beyond simple memory corruption to encompass potential system instability and security implications. Applications utilizing the gfwx crate with affected versions may experience crashes, data loss, or even arbitrary code execution depending on the nature of the memory corruption that occurs. The vulnerability is particularly concerning in multi-threaded environments where concurrent access to image processing operations is common, as it can lead to race conditions that are difficult to reproduce and debug. Attackers could potentially exploit this weakness to manipulate image data in unexpected ways, leading to information disclosure or system compromise through memory corruption attacks. The flaw affects any Rust application that employs the gfwx crate for image processing tasks, making it a widespread concern across software ecosystems that depend on this library.
Mitigation strategies for CVE-2020-36211 require immediate action to upgrade to version 0.3.0 or later of the gfwx crate, which implements proper bounds on the Send and Sync traits for ImageChunkMut. System administrators and developers should conduct thorough code reviews to identify all applications that utilize this crate and ensure proper dependency updates are implemented across the entire software supply chain. Additionally, developers should consider implementing defensive programming practices such as using thread-safe alternatives or proper synchronization mechanisms when working with image data structures. The vulnerability aligns with CWE-362, which describes concurrent execution using shared data without proper synchronization, and may map to ATT&CK technique T1059.007 for potential code injection through memory corruption. Organizations should also implement continuous monitoring for similar vulnerabilities in their dependency tree and establish robust patch management processes to prevent such issues from arising in the future.