HTTP Parameter Pollution · passage 2 of 4

Methodology

1 code block · HTTP Parameter Pollution/README.md

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HTTP Parameter Pollution (HPP) is a web security vulnerability where an attacker injects multiple instances of the same HTTP parameter into a request. The server's behavior when processing duplicate parameters can vary, potentially leading to unexpected or exploitable behavior. HPP can target two levels: * Client-Side HPP: Exploits JavaScript code running on the client (browser). * Server-Side HPP: Exploits how the server processes multiple parameters with the same name. **Examples**:

/app?debug=false&debug=true
/transfer?amount=1&amount=5000

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Data as of 2026-11-15. CVE List through 2026-11-15 · EPSS of 2026-11-14 · CISA KEV checked 2026-11-15. Source: PayloadsAllTheThings by Swissky and contributors, MIT License. For authorised testing only.