# Broken API Versioning Security

> Detects API versioning patterns where newer security controls do not apply to older API versions still in use.

- Skill: `zakirkun/broken-api-versioning-security` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add zakirkun/broken-api-versioning-security`
- Raw SKILL.md: https://api.skillmd.com/api/skills/zakirkun/broken-api-versioning-security/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: zakirkun (https://skillmd.com/u/zakirkun)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/zakirkun/broken-api-versioning-security

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# Broken API Versioning Security

## Overview
When APIs evolve through versions, older versions often lack security controls added in newer versions:
- Authentication may be optional in v1 but required in v2
- Input validation may differ between versions
- Rate limiting may only apply to newer API versions
- Deprecated endpoints may expose functionality removed for security reasons

## Remediation
- Apply identical security controls to ALL active API versions
- Use shared security middleware that applies to all version routes
- Actively sunset old API versions with deprecation notices
- Monitor and alert on old API version usage