Client-side JSON injection (stored DOM-based)
Summary: PortSwigger describes stored DOM-based JSON injection as a flaw where user input is stored and later embedded into a response inside the DOM, then processed unsafely by a client-side script. DOM-based JSON injection specifically occurs when a script incorporates controllable data into a string that is parsed as JSON, letting an attacker construct a URL that causes arbitrary JSON data to be processed when another user visits it.
Key Takeaway: Depending on what that parsed data drives, an attacker can subvert the application's logic or cause unintended actions on behalf of the user - and PortSwigger notes static analysis alone can flag issues that are not actually exploitable, so the finding needs code and execution-path review.
Read the original at PortSwigger Research ↗
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