Security of Rust Applications: Top 10 Vulnerabilities in Practice

Security of Rust Applications: Top 10 Vulnerabilities in Practice

Rust is positioned as a safe systems language capable of preventing entire classes of errors typical of C and C++. However, this does not mean that Rust applications are invulnerable. The ownership system and borrow checker protect against many problems, but unsafe code, logical errors, and external dependencies open up new attack vectors. In this article, we will analyze the 10 most critical vulnerabilities that Rust developers encounter — with real code examples and practical advice on how to fix them.

The material will be useful for both beginners and experienced engineers looking to deepen their knowledge of security in the Rust ecosystem.

1. Unsafe Use of unsafe

The unsafe keyword is the most common source of vulnerabilities in Rust. It disables borrow checker checks and allows working with raw pointers, but full responsibility for correctness falls on the developer.

// Vulnerable code: dereferencing a null pointerfn dangerous() {    let ptr: *const i32 = std::ptr::null();    unsafe {        println!("{}", *ptr); // UB! Segfault    }}

Solution: minimize the use of unsafe. Isolate dangerous operations into separate modules with thorough testing and documented invariants. Use NonNull<T> instead of raw pointers.

2. Data Races

Despite the borrow checker preventing races in safe code, unsafe and incorrect use of synchronization primitives can lead to race conditions.

// Vulnerable code: data race via unsafestatic mut COUNTER: i32 = 0;

fn increment() {    unsafe {        COUNTER += 1; // Non-atomic operation    }}

Solution: use AtomicI32, Mutex, or RwLock. In safe Rust code, data races are impossible — trust the compiler.

3. Integer Overflow

In debug mode, Rust panics on overflow, but in release mode, wrapping occurs by default, which can lead to unexpected behavior.

// Potential vulnerability: overflow logicfn allocate_buffer(size: usize) {    let header_size = 64;    let total = size + header_size; // Can overflow    let buf = vec![0u8; total]; // Panic or small buffer}

Solution: use checked_add(), saturating_add(), or explicit checks. For critical calculations, use the overflow-checks crate.

4. Memory Leaks in unsafe Code

Rust guarantees no leaks in safe code, but unsafe can break this principle. For example, incorrect management of raw pointers or cyclic references with Rc.

// Memory leak: forgot to call dropfn leak_memory() {    let ptr = Box::into_raw(Box::new(42));    // ptr is not freed — leak}

Solution: use Box::from_raw() for correct deallocation. For cyclic references, use Weak or Arc.

5. Unsafe FFI Calls

Calling C functions via FFI (Foreign Function Interface) is one of the main sources of vulnerabilities. Rust cannot control the safety of external code.

// Dangerous FFI: passing an incorrect pointerextern "C" {    fn c_free(ptr: *mut c_void);}

fn free_wrapper(ptr: *mut c_void) {    unsafe { c_free(ptr); } // Double free?}

Solution: use safe wrappers, check buffer boundaries, apply std::ffi::CStr for str