CVE-2026-79749

MCPHub: SSRF Guard Bypass via IPv6 Transition Addresses in URL Validation

Published Aug 31, 2026 CVSS 4.0 · 7.6 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Samanhappy
Samanhappy mcphub
Vendors & Products Samanhappy
Samanhappy mcphub
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title MCPHub: SSRF Guard Bypass via IPv6 Transition Addresses in URL Validation
Weaknesses CWE-918
References
Metrics cvssV4_0

{'score': 7.6, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 31, 2026, 6:48 PM
Reserved
Aug 25, 2026, 2:08 PM
Status
Awaiting Analysis
Published
Aug 31, 2026, 6:17 PM
Modified
Sep 8, 2026, 9:08 PM