# Concurrent Session Issues

> Detects missing concurrent session controls that allow multiple active sessions or fail to invalidate old sessions on new login.

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

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# Concurrent Session Issues

## Overview
Applications without concurrent session controls allow:
- Multiple simultaneous logins from different locations (credential sharing detection fails)
- Old sessions remaining valid after logout from one device
- Session token theft goes undetected because both sessions appear valid

## Remediation
- Implement concurrent session limit (configurable per user tier)
- On new login, optionally invalidate all other sessions
- Provide users with a "log out all other sessions" feature
- Track sessions per user in the database