CVE-2020-35920 in socket2 Crate
Summary
by MITRE • 12/31/2020
An issue was discovered in the socket2 crate before 0.3.16 for Rust. It has false expectations about the std::net::SocketAddr memory representation.
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Analysis
by VulDB Data Team • 06/03/2026
The vulnerability in the socket2 crate prior to version 0.3.16 represents a critical memory representation mismatch that could lead to serious security implications within network applications. This issue stems from the crate's incorrect assumptions about how std::net::SocketAddr structures are internally represented in memory, creating a fundamental disconnect between the expected and actual memory layouts of socket address objects. The socket2 crate serves as a low-level networking abstraction layer in rust applications, making this vulnerability particularly dangerous as it affects the core networking functionality of numerous applications. The flaw manifests when the crate attempts to manipulate or access socket address data structures, leading to potential memory corruption, undefined behavior, or exploitation opportunities. This type of vulnerability falls under the category of memory safety issues that can be exploited through carefully crafted network inputs or by manipulating socket address data during network operations.
The technical implementation of this vulnerability involves the crate's reliance on specific memory layout assumptions that may not hold true across different rust compiler versions or target platforms. When applications using socket2 interact with network sockets, the library's incorrect expectations about SocketAddr memory representation can cause data to be interpreted or accessed at incorrect memory offsets. This misalignment can result in reading from or writing to memory locations that were not intended for the operation, potentially leading to information disclosure, denial of service conditions, or more severe exploitation scenarios. The vulnerability is particularly concerning because socket address manipulation is a fundamental operation in network programming, and any flaw in this area can have cascading effects throughout the application's networking stack. This issue demonstrates how seemingly minor assumptions about standard library types can create significant security risks in systems that depend heavily on memory safety guarantees provided by the programming language runtime.
The operational impact of this vulnerability extends across numerous rust applications that depend on the socket2 crate for network functionality, potentially affecting web servers, network clients, and any application requiring low-level socket operations. Attackers could exploit this vulnerability by crafting specific network traffic or socket address data that triggers the memory representation mismatch, leading to unpredictable application behavior or potential remote code execution in some scenarios. The vulnerability's exploitation potential is enhanced by the fact that socket2 is a widely used crate in the rust ecosystem, meaning that a large number of applications could be affected simultaneously. Organizations relying on rust-based network services may experience service disruptions, data integrity issues, or security breaches if they have not updated to version 0.3.16 or later. This vulnerability also highlights the importance of careful consideration when building abstractions over standard library types, as assumptions about internal representations can quickly become problematic when dealing with language implementations that may evolve or have platform-specific behaviors.
Mitigation strategies for this vulnerability primarily involve updating to socket2 version 0.3.16 or later, where the memory representation assumptions have been corrected to properly align with the actual std::net::SocketAddr layout. System administrators and developers should conduct thorough testing of their applications after applying the update to ensure compatibility and verify that no regressions have been introduced. Additionally, organizations should review their dependency management practices to ensure that all network-related crates are kept up to date with security patches. The vulnerability underscores the importance of following security best practices such as implementing automated dependency monitoring and vulnerability scanning in development pipelines. Security teams should also consider implementing network segmentation and monitoring to detect potential exploitation attempts targeting this type of memory safety vulnerability. This incident serves as a reminder of the critical nature of memory safety in systems programming and the need for thorough testing of low-level abstractions, particularly those that interface with standard library components that may have implementation details not immediately obvious to library consumers.
This vulnerability aligns with several common weakness enumerations including CWE-121, which addresses stack-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read scenarios. The issue also relates to ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation may involve crafting specific inputs that trigger the memory representation problems, potentially leading to arbitrary code execution. The memory safety implications of this vulnerability make it particularly relevant to the broader category of software security weaknesses that can be addressed through proper testing methodologies, static analysis tools, and adherence to secure coding practices in systems programming environments. Organizations should implement comprehensive security testing procedures including memory safety verification and fuzzing to identify similar issues in their codebases and dependencies.