Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| modelcontextprotocol | go-sdk | < 1.4.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260326T203309-150000.1.155.2 | SUSE-SU-2026:1135-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | ferretdb | 2.7.0-r10 | — |
| Wolfi rolling | glab | 1.90.0-r0 | — |
| Wolfi rolling | jaeger-2-jaeger | 2.16.0-r3 | — |
| Wolfi rolling | opencost | 1.119.2-r7 | — |
| Wolfi rolling | osv-scanner | 2.3.3-r7 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/modelcontextprotocol/go-sdk | < 1.4.1 | 1.4.1 | GHSA-89xv-2j6f-qhc8 |
Advisories 2
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:1135-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 31, 2026