Summary

Strapi's password hashing implementation using bcryptjs lacks maximum password length validation. Since bcryptjs truncates passwords exceeding 72 bytes, this creates potential vulnerabilities such as authentication bypass and performance degradation.

POC Create an admin user with a password exceeding 72 characters like 85, Log in using only the first 72 characters of the password. Authentication is successful, confirming the issue.

Proposed Solution Based on discussions:

Add a maximum password length validation (72 characters) during password creation and updates for both Admin and U&P users. Truncate passwords exceeding 72 bytes on the server before passing them to bcryptjs during login. Optionally, issue a warning to users with passwords longer than 72 bytes during login, informing them of truncation.

Impact This issue affects all Strapi installations using bcryptjs for password hashing. Until resolved, it can lead to: Authentication Bypass: Users may unknowingly set passwords exceeding 72 bytes, leading to truncated, predictable hashes. Performance Issues: Excessively long passwords can degrade server performance.