What’s Vulnerable › Vulnerabilities

CVE-2026-79749: MCPHub: SSRF Guard Bypass via IPv6 Transition Addresses in URL Validation

• Severity: high (CVSS 7.6 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-31 · updated 2026-09-08
• Weakness: CWE-918

Description

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.

Affected products

• samanhappy mcphub: before 1.0.32

References

• https://github.com/samanhappy/mcphub/commit/2b10ae36112ce68deebf910b22505d44efcef552
• https://github.com/samanhappy/mcphub/pull/1069
• https://github.com/samanhappy/mcphub/releases/tag/v1.0.32
• https://github.com/samanhappy/mcphub/security/advisories/GHSA-pr4x-3pc7-2fhw
• https://github.com/samanhappy/mcphub/security/advisories/GHSA-pr4x-3pc7-2fhw

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