Lab: JWT authentication bypass via unverified signature
Summary: A PortSwigger Web Security Academy lab demonstrates a JWT authentication bypass in which the server does not verify the signature on any JWT it receives. By changing the sub claim in the token payload from wiener to administrator, a logged-in user reaches the /admin panel and can delete the user carlos.
Why it matters: A single unverified signature turns a normal user's own session token into administrator access, and the lab's path from /my-account to /admin/delete?username=carlos shows how quickly that becomes account deletion.
Read the original at PortSwigger Research ↗
- Topics
- Vulnerabilities & Patching
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