CVE-2020-35882 in rocket Crate
Summary
by MITRE • 12/31/2020
An issue was discovered in the rocket crate before 0.4.5 for Rust. LocalRequest::clone creates more than one mutable references to the same object, possibly causing a data race.
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Analysis
by VulDB Data Team • 06/24/2026
The vulnerability identified in the rocket crate versions prior to 045 represents a critical concurrency flaw that undermines memory safety guarantees within Rust applications. This issue manifests through the LocalRequest::clone method which inadvertently creates multiple mutable references to identical objects, fundamentally violating Rust's ownership model and creating potential data race conditions. The flaw exists at the core of the web framework's request handling mechanism where cloning operations can lead to undefined behavior when multiple mutable borrows attempt to access the same memory location simultaneously.
The technical implementation of this vulnerability stems from improper handling of reference counting and ownership semantics within the rocket framework's internal request management system. When LocalRequest::clone is invoked, it fails to properly enforce Rust's borrowing rules that prevent multiple mutable references to the same data. This creates a scenario where concurrent access patterns can result in memory corruption, leading to application crashes or potentially exploitable conditions. The issue directly relates to CWE-362 which describes concurrent execution with unrestrained resource consumption, and more specifically maps to CWE-119 which addresses weak buffer access protections. From an ATT&CK perspective, this vulnerability could enable privilege escalation through process memory corruption or facilitate denial of service attacks by causing application instability.
The operational impact of this vulnerability extends beyond simple memory safety concerns to potentially compromise entire application deployments. Applications built on rocket framework versions prior to 045 may experience unexpected crashes during high-concurrency request processing scenarios where multiple threads attempt to modify cloned request objects simultaneously. This vulnerability particularly affects web applications that rely heavily on concurrent request handling, making it especially dangerous in production environments where throughput and reliability are critical. The risk assessment indicates this could lead to complete application failure or provide attackers with opportunities to execute arbitrary code through memory corruption exploitation techniques.
Mitigation strategies for this vulnerability require immediate upgrading to rocket crate version 045 or later where the cloning mechanism has been properly implemented to maintain memory safety guarantees. System administrators should conduct thorough security assessments of all applications using affected versions and implement comprehensive monitoring for unusual crash patterns or performance degradation that might indicate exploitation attempts. Additionally, developers should review their codebases for any custom implementations that might rely on similar cloning patterns and ensure proper adherence to Rust's ownership principles. The fix implemented in version 045 addresses the core issue by ensuring that cloned request objects maintain proper reference semantics and do not create conflicting mutable borrows. Organizations should also consider implementing runtime protections such as address sanitizers or memory protection mechanisms during development phases to detect similar issues in other components of their software stack.