# Type Coercion Security Bugs

- ID: javascript-type-coercion-bugs
- Severity: MEDIUM
- CWE: CWE-1024 (CWE-1024)
- Languages: JavaScript, TypeScript
- Frameworks: all

## Description

Detects unsafe use of loose equality operators (==, !=) and type coercion patterns
that can lead to security vulnerabilities. JavaScript's type coercion can cause
unexpected behavior in security-critical code.

Common security issues from type coercion:
1. Authentication bypass: password == null matches both null AND undefined
2. Authorization bypass: role == "admin" can be bypassed with role = true
3. Input validation bypass: value == 0 matches "", [], false, "0"
4. SQL/NoSQL injection: params == {} doesn't check for actual object properties

Type coercion rules in JavaScript:
- null == undefined (true)
- 0 == "" == false == [] (all true)
- "0" == 0 (true)
- " \t\n" == 0 (true)
- But: "0" != false (because string vs boolean)

Security implications are severe when used in:
- Authentication/authorization checks
- Input validation
- Null/undefined checks
- Role/permission comparisons

## Detection Message

Loose equality operator {operator} used in security-critical context: {context}

## Remediation

Use strict equality (===, !==) to avoid type coercion bugs.

## Documentation

[object Object]