Vulnerability · Published Aug 31, 2026 · Assigned by GitHub_M

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

High 7.6

In plain English

A high-severity server-side request forgery in mcphub from samanhappy. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities).

Severity (CVSS 4.0)7.6High

Exploit odds (30 days)0.4%top 60.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
samanhappy	mcphub	< 1.0.32

Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

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