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 0.01% · 0.9th 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
0.01%
0.9th 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