CVE-2026-49857

auth-fetch-mcp has an SSRF protection bypass via IPv4-mapped IPv6 loopback. The root cause is in isPrivateV6() handling of hex-normalized IPv4-mapped addresses; input like http://[::ffff:127.0.0.1]:PORT/ becomes http://[::ffff:7f00:1]:PORT/ and net.isIPv4 returns false, allowing requests to priva...