# Cwe 833 Deadlock

> Use this skill when you need to remediate CWE-833 (Deadlock) vulnerabilities in Java code. Triggers on SAST findings, security reviews, or when fixing deadlock issues.

- Skill: `developerscoffee/cwe-833-deadlock` (Agent Skill)
- Install (CLI): `npx skillmds@latest add developerscoffee/cwe-833-deadlock`
- Raw SKILL.md: https://api.skillmd.com/api/skills/developerscoffee/cwe-833-deadlock/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: DevelopersCoffee (https://skillmd.com/u/developerscoffee)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/developerscoffee/cwe-833-deadlock

---


# CWE-833 Deadlock

## Description

Deadlock

Reference:
https://cwe.mitre.org/data/definitions/833.html


**OWASP Category**: A04:2021 – Insecure Design


---

## Vulnerable Pattern


### ❌ Example 1: Vulnerable Pattern

```java
// VULNERABLE: Potential deadlock - different lock ordering
public void transferMoney(Account from, Account to, int amount) {
    synchronized (from) {
        synchronized (to) {
            from.withdraw(amount);
            to.deposit(amount);
        }
    }
}
```


**Why it's vulnerable:** This pattern is vulnerable to Deadlock




---

## Deterministic Fix


### ✅ Secure Implementation: Secure Implementation

```java
// SECURE: Consistent lock ordering
public void transferMoney(Account from, Account to, int amount) {
    Account first = from.getId() < to.getId() ? from : to;
    Account second = from.getId() < to.getId() ? to : from;

    synchronized (first) {
        synchronized (second) {
            from.withdraw(amount);
            to.deposit(amount);
        }
    }
}
```


**Why it's secure:** Implements proper protection against Deadlock




---

## Detection Pattern

Look for these patterns in your codebase:


```bash
# Find nested synchronized
grep -rn "synchronized.*{" --include="*.java" -A10 | grep "synchronized"
```



---

## Remediation Steps


1. Always acquire locks in consistent order

2. Use Lock.tryLock() with timeout

3. Consider lock-free data structures

4. Use higher-level concurrency utilities


---

## Key Imports

```java

import java.util.concurrent.locks.Lock;

```

---

## Verification

After remediation:


- Run SAST scanner to confirm vulnerability is resolved

- Review all instances of the vulnerable pattern

- Add unit tests that verify the secure implementation

- Check for similar patterns in related code


---

## Trigger Examples

```
Fix CWE-833 vulnerability
Resolve Deadlock issue
Secure this Java code against deadlock
SAST reports CWE-833
```

---

## Common Vulnerable Locations

| Layer | Files | Patterns |
|-------|-------|----------|

| Controller | `*Controller.java` | User input handling |

| Service | `*Service.java` | Business logic |

| Repository | `*Repository.java` | Data access |


---

## References


- [CWE-833: Deadlock](https://cwe.mitre.org/data/definitions/833.html)


---

**Source**: Generated by [Java CWE Security Skills Generator](https://github.com/DevelopersCoffee/java-cwe-security-skills)
**Last Updated**: 2026-03-07