RUSTSEC-2020-0133: 
Rust vulnerability analysis and mitigation

A security vulnerability was identified in the scottqueue crate for Rust, tracked as RUSTSEC-2020-0133 (CVE-2020-36453). The issue, discovered and disclosed in November 2020, affects versions through 2020-11-15. The vulnerability stems from unconditional implementations of Send and Sync traits for Queue, which could lead to potential thread safety issues (RustSec Advisory).

The vulnerability involves the Queue object implementing Send and Sync traits unconditionally without proper bounds checking. The technical issue lies in the implementation where Send and Sync traits are declared without the necessary T: Send bound, potentially allowing unsafe thread interactions with types that should never be sent across threads, such as Rc or references to cells. The vulnerability has been assigned a CVSS v3.1 base score of 8.1 (HIGH) with the vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability could lead to data races and undefined behavior when using certain types across threads. This could potentially result in memory safety violations and segmentation faults when dealing with types like Cell that are not meant to be shared between threads. A proof-of-concept demonstrates that this can lead to segmentation faults when manipulating shared references (GitHub Issue).

The vulnerability can be exploited in scenarios where the Queue type is used with non-Send types across thread boundaries. A practical exploit has been demonstrated using Cell types, showing how the vulnerability can lead to data races and memory corruption (GitHub Issue).

The recommended mitigation is to add proper Send bounds to the Send and Sync trait implementations for Queue. Users should update to a version that includes these fixes or avoid using the affected versions of the scottqueue crate (RustSec Advisory).