# What is Use-After-Free?

*Development · Last updated: November 1, 2026*

> UAF

It is a vulnerability that occurs when a program tries to access a memory area after it has been freed.

## Overview

Use-after-free occurs during memory management when a pointer continues to point to an address even after the data structure has been deleted or freed. The program reading or writing to this invalid address leads to unexpected crashes or malicious code execution. Languages like Rust, which enforce memory safety at compile time, are specifically designed to prevent such errors.

***Analogy:** It is similar to returning a hotel room key, then trying to enter the room again and tamper with the belongings of the new guest staying there.*

## How it works

The programmer or memory manager frees a memory block but does not reset the variable pointing to that block. When the program attempts to perform operations using this dangling pointer in subsequent steps, a memory error occurs.

## Where it is used

It is frequently seen in system programming languages that require manual memory management, such as C and C++, as well as in scanned security vulnerabilities and vulnerability analyses.

## Commonly confused with

While a memory leak vulnerability is the failure to free unused memory, use-after-free is the erroneous reuse of freed memory.

## Questions and answers

**How can this vulnerability be prevented?**

It is prevented by resetting pointers immediately after the memory is freed or by choosing languages that provide memory safety.

**Does this vulnerability allow remote code execution?**

Yes, attackers can control the execution flow by writing their own data into the freed memory area.

## Related terms

- [Vulnerability Scanning](https://trescout.com/en/dictionary/vulnerability-scanning/)
- [Systems Programming](https://trescout.com/en/dictionary/systems-programming/)
- [Rust](https://trescout.com/en/dictionary/rust/)
- [Borrow Checker](https://trescout.com/en/dictionary/borrow-checker/)
- [Remote Code Execution](https://trescout.com/en/dictionary/rce/)

This explanation was written in plain language for TreScout with AI and **machine-translated** from the Turkish original · the Turkish version prevails. If something looks wrong or missing, write to [hello@trescout.com](mailto:hello@trescout.com). [Read in Turkish →](https://trescout.com/dictionary/use-after-free/)

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Source: TreScout Dictionary · https://trescout.com/en/dictionary/use-after-free/