VDB
CVE-2026-33252
CVE-2026-33252
PUBLISHED
CVSS 7.099999904632568 HIGH
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.
EPSS 0.18% · 7.3th percentile
Risk Scores
CVSS 3.1
7.099999904632568
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
EPSS Score
0.18%
7.3th percentile
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| github.com | modelcontextprotocol/go-sdk | 0, 0, 0 |
| modelcontextprotocol | go-sdk | < 1.4.1, < 1.4.1, < 1.4.1 |
Timeline
- Mar 19, 2026 CVE Published
- Mar 20, 2026 Security Advisory
- Mar 24, 2026 EPSS Score
- Mar 25, 2026 CVE Updated
- Mar 25, 2026 EPSS Score
- May 18, 2026 EPSS Score
- May 19, 2026 EPSS Score
- May 20, 2026 EPSS Score
- May 21, 2026 EPSS Score
- May 22, 2026 EPSS Score
- May 23, 2026 EPSS Score
- May 24, 2026 EPSS Score
References
- https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-89xv-2j6f-qhc8 technical
- https://github.com/modelcontextprotocol/go-sdk package
- https://nvd.nist.gov/vuln/detail/CVE-2026-33252 advisory
- https://github.com/modelcontextprotocol/go-sdk/commit/a433a831d6e5d5ac3b9e625a8095aa8eaa040dfc fix