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NVD Vulnerability Details :
CVE-2026-44430
Modified
More InfoOfficial Page
Source-security-advisories@github.com
View Known Exploited Vulnerability (KEV) details
Published At-14 May, 2026 | 21:16
Updated At-15 May, 2026 | 19:16

The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, the Registry's HTTP-based namespace verification (POST /v0/auth/http, POST /v0.1/auth/http) uses safeDialContext (internal/api/handlers/v0/auth/http.go:67-110) to refuse dialling private/internal addresses when fetching the well-known public-key file from a publisher-supplied domain. The blocklist (isBlockedIP, lines 125-133) relies entirely on Go stdlib's IsLoopback / IsPrivate / IsLinkLocalUnicast / IsMulticast / IsUnspecified plus a manual CGNAT range. None of these cover IPv6 6to4 (2002::/16), NAT64 (64:ff9b::/96 and 64:ff9b:1::/48 per RFC 8215), or deprecated site-local (fec0::/10) — all of which encode arbitrary IPv4 in the address bits and tunnel to RFC1918 / cloud-metadata services on dual-stack / NAT64-enabled hosts. This vulnerability is fixed in 1.7.7.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary4.06.3MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/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
Primary3.14.0MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Type: Secondary
Version: 4.0
Base score: 6.3
Base severity: MEDIUM
Vector:
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/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
Type: Primary
Version: 3.1
Base score: 4.0
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
CPE Matches
lfprojects
lfprojects
>>mcp_registry>>Versions before 1.7.7(exclusive)
cpe:2.3:a:lfprojects:mcp_registry:*:*:*:*:*:*:*:*
Weaknesses
CWE IDTypeSource
CWE-918Secondarysecurity-advisories@github.com
CWE ID: CWE-918
Type: Secondary
Source: security-advisories@github.com
Evaluator Description
Evaluator Impact

Evaluator Solution

Vendor Statements
References
HyperlinkSourceResource
https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6vsecurity-advisories@github.com
Exploit
Vendor Advisory
https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6v134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit
Vendor Advisory
Hyperlink: https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6v
Source: security-advisories@github.com
Resource:
Exploit
Vendor Advisory
Hyperlink: https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-r48c-v28r-pf6v
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Resource:
Exploit
Vendor Advisory
Change History
0Changes found
Details not found