CVE-2026-79749
MCPHub: SSRF Guard Bypass via IPv6 Transition Addresses in URL Validation
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.
INFO
Published Date :
Aug. 31, 2026, 6:17 p.m.
Last Modified :
Aug. 31, 2026, 6:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-79749
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update MCPHub to version 1.0.32.
- Apply relevant security patches if updating is not possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-79749.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-79749 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-79749
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-79749 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-79749 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Aug. 31, 2026
Action Type Old Value New Value 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. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-918 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/79xxx/CVE-2026-79749.json">CVE-2026-79749</a> Added Reference https://github.com/samanhappy/mcphub/commit/2b10ae36112ce68deebf910b22505d44efcef552 Added Reference https://github.com/samanhappy/mcphub/pull/1069 Added Reference https://github.com/samanhappy/mcphub/releases/tag/v1.0.32 Added Reference https://github.com/samanhappy/mcphub/security/advisories/GHSA-pr4x-3pc7-2fhw