RUSTSEC-2021-0030: 
Rust vulnerability analysis and mitigation

A double-free vulnerability was discovered in the scratchpad crate versions before 1.3.1 for Rust, identified as RUSTSEC-2021-0030. The vulnerability was found by the Rust group at Georgia Tech's Systems Software & Security Lab (sslab-gatech) while scanning Rust code on crates.io. The issue was reported on February 18, 2021, affecting the move_elements function in the crate (GitHub Issue).

The vulnerability occurs in the move_elements function where a double-free condition can arise upon a panic in a user-provided closure function. The issue affects two specific functions: ::Item]>::move_elements() and traits::SliceMoveSource>::move_elements(). The vulnerability has been assigned a CVSS v3.1 base score of 9.8 (CRITICAL) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating high severity across confidentiality, integrity, and availability impacts (NVD).

When exploited, this vulnerability can lead to undefined behavior in safe Rust code. The double-free condition can occur when an object is dropped twice upon panic in the user-provided closure, potentially leading to memory corruption and program crashes (GitHub Issue).

The vulnerability can be triggered through safe Rust code without requiring unsafe blocks. A proof-of-concept exists demonstrating the issue using a simple struct with a Drop implementation, where the drop function is called twice when a panic occurs in the closure passed to move_elements (GitHub Issue).

The vulnerability has been fixed in version 1.3.1 of the scratchpad crate. Users are advised to upgrade to this version or later to address the double-free issue (NVD).