V 0.5.2 SSRF Bypass via Parser Differential in net.urllib and net.http

Summary

V through 0.5.2, fixed in commit 85859f0, contains a server-side request forgery (SSRF) bypass vulnerability that allows attackers to circumvent host-based allowlists by exploiting a parser differential between net.urllib and net.http. Attackers can craft a URL containing a backslash in the authority section such that net.urllib.parse() extracts the trusted host for allowlist validation while net.http.get() normalizes the backslash and connects to the internal host, enabling access to internal network services that the allowlist was intended to block.