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5 vulnerabilities found for registry by modelcontextprotocol
CVE-2026-44428 (GCVE-0-2026-44428)
Vulnerability from cvelistv5
Published
2026-05-14 21:09
Modified
2026-05-15 14:22
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Summary
The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.6, the client-side and server-side GitHub OIDC flow is bound only to a global audience string, not to the specific registry instance being targeted. On the client side, the publisher always appends audience=mcp-registry when requesting the GitHub Actions ID token, regardless of the selected --registry URL. On the server side, the exchange endpoint validates only that same fixed audience and then derives publish permissions directly from repository_owner. As a result, a token legitimately obtained while interacting with one registry deployment remains acceptable to any other deployment that shares the same code and audience string. This vulnerability is fixed in 1.7.6.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | registry |
Version: < 1.7.6 |
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CVE-2026-44427 (GCVE-0-2026-44427)
Vulnerability from cvelistv5
Published
2026-05-14 21:07
Modified
2026-05-15 13:33
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
Summary
The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. From 1.1.0 to 1.7.4, the TrailingSlashMiddleware in internal/api/server.go is vulnerable to an open redirect attack. An attacker can craft a URL with a protocol-relative path (e.g., //evil.com/) that, after trailing slash removal, results in a Location header of //evil.com — which browsers interpret as an absolute URL to an external domain. This vulnerability is fixed in 1.7.5.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | registry |
Version: >= 1.1.0, < 1.7.5 |
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CVE-2026-44429 (GCVE-0-2026-44429)
Vulnerability from cvelistv5
Published
2026-05-14 21:05
Modified
2026-05-15 14:20
Severity ?
VLAI Severity ?
EPSS score ?
CWE
Summary
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 public catalogue UI served at GET / (file internal/api/handlers/v0/ui_index.html) is vulnerable to stored cross-site scripting via the server.websiteUrl field of any published server.json. Server-side validation in internal/validators/validators.go (validateWebsiteURL) only checks that the URL parses, is absolute, and uses the https scheme; it does not reject quote characters. Client-side, the value is interpolated into a double-quoted href attribute via innerHTML, using a homegrown escapeHtml helper that performs the standard textContent → innerHTML round-trip. Per the HTML serialisation algorithm, that round-trip encodes only &, <, > and U+00A0 inside text nodes — it does not encode " or '. A literal " in websiteUrl therefore breaks out of the href attribute, allowing arbitrary on* event handlers to be appended to the same <a> element. The Content-Security-Policy on / is script-src 'self' 'unsafe-inline' https://cdn.tailwindcss.com, so the injected event handlers execute. Any user able to obtain a publish token (e.g. via POST /v0/auth/github-at with their own GitHub account, or POST /v0/auth/none on a deployment that has anonymous auth enabled) can plant a poisoned record visible to every visitor of the registry homepage. This vulnerability is fixed in 1.7.7.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | registry |
Version: < 1.7.7 |
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CVE-2026-44430 (GCVE-0-2026-44430)
Vulnerability from cvelistv5
Published
2026-05-14 21:02
Modified
2026-05-15 18:05
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Summary
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.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | registry |
Version: < 1.7.7 |
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CVE-2026-45781 (GCVE-0-2026-45781)
Vulnerability from cvelistv5
Published
2026-05-14 21:00
Modified
2026-05-16 01:06
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-636 - Not Failing Securely ('Failing Open')
Summary
The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.9, OCI ownership validation skips label-match check when upstream OCI registry returns HTTP 429, letting any authenticated publisher bind their io.github.<user>/* namespace to OCI images they do not control. internal/validators/registries/oci.go:104-119 fails open on http.StatusTooManyRequests: when the registry's anonymous fetch to the upstream OCI registry is rate-limited, ValidateOCI returns nil and the publish is accepted without ever running the io.modelcontextprotocol.server.name label-match check at lines 122-141. That label check is the only cross-system ownership proof the registry applies to OCI packages — every other registry type (NPM, PyPI, NuGet, MCPB) treats a non-200 upstream response as a hard error. This vulnerability is fixed in 1.7.9.
References
| URL | Tags | |
|---|---|---|
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | registry |
Version: < 1.7.9 |
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"exploit"
],
"url": "https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-2v5f-5r6w-p67r"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "registry",
"vendor": "modelcontextprotocol",
"versions": [
{
"status": "affected",
"version": "\u003c 1.7.9"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.9, OCI ownership validation skips label-match check when upstream OCI registry returns HTTP 429, letting any authenticated publisher bind their io.github.\u003cuser\u003e/* namespace to OCI images they do not control. internal/validators/registries/oci.go:104-119 fails open on http.StatusTooManyRequests: when the registry\u0027s anonymous fetch to the upstream OCI registry is rate-limited, ValidateOCI returns nil and the publish is accepted without ever running the io.modelcontextprotocol.server.name label-match check at lines 122-141. That label check is the only cross-system ownership proof the registry applies to OCI packages \u2014 every other registry type (NPM, PyPI, NuGet, MCPB) treats a non-200 upstream response as a hard error. This vulnerability is fixed in 1.7.9."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 3.5,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-636",
"description": "CWE-636: Not Failing Securely (\u0027Failing Open\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-05-14T21:00:49.961Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-2v5f-5r6w-p67r",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-2v5f-5r6w-p67r"
}
],
"source": {
"advisory": "GHSA-2v5f-5r6w-p67r",
"discovery": "UNKNOWN"
},
"title": "MCP Registry: OCI ownership validation fails open on upstream rate limits, allowing attacker-controlled package claims"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-45781",
"datePublished": "2026-05-14T21:00:49.961Z",
"dateReserved": "2026-05-13T07:45:21.252Z",
"dateUpdated": "2026-05-16T01:06:38.302Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}