CVE-2026-33252

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Source
https://cve.org/CVERecord?id=CVE-2026-33252
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33252.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33252
Aliases
Downstream
Related
Published
2026-03-23T23:44:16.106Z
Modified
2026-04-02T13:27:13.540629Z
Severity
  • 7.1 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L CVSS Calculator
Summary
MCP Go SDK Allows Cross-Site Tool Execution for HTTP Servers without Authorizatrion
Details

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site POST requests without validating the Origin header and without requiring Content-Type: application/json. In deployments without Authorization, especially stateless or sessionless configurations, this allows an arbitrary website to send MCP requests to a local server and potentially trigger tool execution. Version 1.4.1 contains a patch for the issue.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33252.json",
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-352"
    ]
}
References

Affected packages

Git / github.com/modelcontextprotocol/go-sdk

Affected ranges

Type
GIT
Repo
https://github.com/modelcontextprotocol/go-sdk
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
580f2a09be5c5b7ed4d868aa74ad1019dfd5160a
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.4.1"
        }
    ]
}

Affected versions

v0.*
v0.1.0
v0.2.0
v0.3.0
v0.3.1
v0.4.0
v0.5.0
v0.6.0
v0.7.0
v0.8.0
v1.*
v1.0.0
v1.1.0
v1.1.0-pre.1
v1.1.0-pre.2
v1.2.0
v1.2.0-pre.1
v1.2.0-pre.2
v1.3.0
v1.3.0-pre.1
v1.3.1
v1.4.0
v1.5.0-pre.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33252.json"