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Lab 347 — PushRelay — SSRF via URL Parsing Confusion in Webhook Tester

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Task: PushRelay webhook platform validates URLs against SSRF blocklist using WHATWG URL parser, but misses IPv6-mapped IPv4 addresses. Solution: Bypass blocklist with http://[::ffff:127.0.0.1]:3001/ to reach internal config service and retrieve the flag.

$ ls tags/ techniques/
ssrf_localhost_bypassurl_validation_bypassinternal_service_accessipv4_mapped_ipv6_bypass

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