CVE-2026-79749 — MCPHub: SSRF Guard Bypass via IPv6 Transition Addresses in URL Validation
MCPHub is a unified hub for centrally managing and dynamically orchestrating multiple MCP servers/APIs into separate endpoints with flexible routing strategies. Prior to version…
Published: 2026-08-31 · CVSS: 7.6 · CVSS 4.0
MCPHub is a unified hub for centrally managing and dynamically orchestrating multiple MCP servers/APIs into separate endpoints with flexible routing strategies. Prior to version 1.0.32, MCPHub's SSRF guard in src/utils/ssrf.ts uses a custom isBlockedIpv6 function that only checks for loopback, link-local, unique-local, IPv4-mapped, and IPv4-compatible IPv6 addresses. IPv6 transition address families -- NAT64 (64:ff9b::/96), 6to4 (2002::/16), and Teredo (2001::/32) -- are not checked. An attacker who can specify a URL for an MCP server connection can encode a private IPv4 address inside one of these IPv6 forms to bypass the SSRF guard and reach internal infrastructure. This issue has been patched in version 1.0.32.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7