GraphQL Authorization Bypass: A Real CVE Code Review
A real-world GraphQL authorization bypass vulnerability allows attackers to access private user data without forged tokens or malformed requests by exploiting missing checks in nested resolvers. The issue arises when authorization is only enforced at the query root, leaving deeper resolvers exposed even under valid queries. This class of bug affects Apollo-based APIs and was exemplified by CVE-2023-26489, where tenant isolation failed due to improper resolver-level protections.
- ▪GraphQL APIs can suffer from authorization bypass if checks are only applied at the root resolver and not enforced in nested resolvers.
- ▪The vulnerability allows authenticated users to query private data of other users by exploiting resolvers that lack ownership or access checks.
- ▪Aliases, fragments, and batched operations in GraphQL can obscure malicious activity from logging and rate-limiting systems.
- ▪Resolver functions must receive and validate the request context to prevent unauthorized data exposure, regardless of query structure.
- ▪Field-level authorization must be implemented in every sensitive resolver to defend against traversal attacks through valid query paths.
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try { if(localStorage) { let currentUser = localStorage.getItem('current_user'); if (currentUser) { currentUser = JSON.parse(currentUser); if (currentUser.id === 1585924) { document.getElementById('article-show-container').classList.add('current-user-is-article-author'); } } } } catch (e) { console.error(e); } Stefan Posted on May 17 • Originally published at codereviewlab.com GraphQL Authorization Bypass: A Real CVE Code Review #graphql #security #appsec #codereview Real-World GraphQL Authorization Bypass CVE Example Code Review A tenant isolation bug in a GraphQL API differs from a REST IDOR in one uncomfortable way: the bypass often doesn't require a forged token, a path traversal, or a malformed request.
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