CVE-2026-116686 (GCVE-0-2026-116686)
Vulnerability from cvelistv5
Published
2026-10-27 19:29
Modified
2026-10-28 16:13
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Summary
The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client's network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0.
References
| URL | Tags | |
|---|---|---|
|
|
||
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| modelcontextprotocol | python-sdk |
Version: >= 1.10.0, < 1.30.0 Version: >= 2.0.0, < 2.2.0 |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-116686",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-10-28T14:34:36.544931Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-10-28T16:13:45.473Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "python-sdk",
"vendor": "modelcontextprotocol",
"versions": [
{
"status": "affected",
"version": "\u003e= 1.10.0, \u003c 1.30.0"
},
{
"status": "affected",
"version": "\u003e= 2.0.0, \u003c 2.2.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema\u0027s default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client\u0027s network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-918",
"description": "CWE-918: Server-Side Request Forgery (SSRF)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-27T19:29:16.001Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/pull/3394",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/pull/3394"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/pull/3396",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/pull/3396"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0"
},
{
"name": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0"
}
],
"source": {
"advisory": "GHSA-rwrf-2pqf-9j8j",
"discovery": "UNKNOWN"
},
"title": "Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-116686",
"datePublished": "2026-10-27T19:29:16.001Z",
"dateReserved": "2026-10-26T20:00:59.830Z",
"dateUpdated": "2026-10-28T16:13:45.473Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-116686\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-10-28T14:34:36.544931Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-10-28T14:34:41.665Z\"}}], \"cna\": {\"title\": \"Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas\", \"source\": {\"advisory\": \"GHSA-rwrf-2pqf-9j8j\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 6.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"REQUIRED\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"modelcontextprotocol\", \"product\": \"python-sdk\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003e= 1.10.0, \u003c 1.30.0\"}, {\"status\": \"affected\", \"version\": \"\u003e= 2.0.0, \u003c 2.2.0\"}]}], \"references\": [{\"url\": \"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/pull/3394\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/pull/3394\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/pull/3396\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/pull/3396\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0\", \"name\": \"https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema\u0027s default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client\u0027s network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-918\", \"description\": \"CWE-918: Server-Side Request Forgery (SSRF)\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-10-27T19:29:16.001Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-116686\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-28T16:13:45.473Z\", \"dateReserved\": \"2026-10-26T20:00:59.830Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-10-27T19:29:16.001Z\", \"assignerShortName\": \"GitHub_M\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…