IDOR
An access control vulnerability in which an application uses user-controllable input, such as an ID in a URL parameter, to locate internal objects without verifying authorization. It is a common high-severity item in the OWASP Top 10.
Timeline (last 90 days)
A developer shared on Reddit that Claude Opus 5.5 proactively discovered an IDOR vulnerability in their SaaS application's invoice endpoint during a code refactoring process (any logged-in user could retrieve other companies' invoices by modifying the ID in the URL).
IDOR arises because the application directly uses user-controllable input (such as URL parameters or IDs in form fields) to locate internal objects, yet does not verify on the server side whether the current user is authorized to access that object.
The core of IDOR remediation is to perform a server-side authorization check before every object access, combined with the use of unpredictable identifiers (such as UUIDs) as defense in depth.
The subsequent code review tools CodeRabbit and Codex Review discovered the same IDOR vulnerability in the PR and discussed it smoothly, with CodeRabbit additionally flagging two similar endpoints and providing actionable remediation suggestions.
All Facts (4)
IDOR arises because the application directly uses user-controllable input (such as URL parameters or IDs in form fields) to locate internal objects, yet does not verify on the server side whether the current user is authorized to access that object.
50%UnverifiedThe core of IDOR remediation is to perform a server-side authorization check before every object access, combined with the use of unpredictable identifiers (such as UUIDs) as defense in depth.
50%UnverifiedA developer shared on Reddit that Claude Opus 5.5 proactively discovered an IDOR vulnerability in their SaaS application's invoice endpoint during a code refactoring process (any logged-in user could retrieve other companies' invoices by modifying the ID in the URL).
50%UnverifiedThe subsequent code review tools CodeRabbit and Codex Review discovered the same IDOR vulnerability in the PR and discussed it smoothly, with CodeRabbit additionally flagging two similar endpoints and providing actionable remediation suggestions.
50%