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TI-2026-25670 Aliases CVE-2026-33252GHSA-89xv-2j6f-qhc8

MCP Go SDK Allows Cross-Site Tool Execution for HTTP Servers without Authorizatrion

Priority LOW 30CWE-352Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Tampering
Confidentiality · integrity · availability
None · High · Low
Fix status
Partial Red Hat: 1 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-352.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00181 7th percentileScored 2026-11-07
Fix Partial go-sdk (modelcontextprotocol): 1.4.1github.com/modelcontextprotocol/go-sdk (Go): 1.4.1Red Hat: 1 advisoryRed Hat: 1 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MLflowgo-sdkbefore 1.4.11.4.1Patch availableCNA
—github.com/modelcontextprotocol/go-sdk (Go)before 1.4.11.4.1Patch availableGHSA-89xv-2j6f-qhc8
  • go-sdk VendorMLflow Affected before 1.4.1 Fixed in 1.4.1 Patch available CNA
  • github.com/modelcontextprotocol/go-sdk (Go) Vendor— Affected before 1.4.1 Fixed in 1.4.1 Patch available GHSA-89xv-2j6f-qhc8

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:lfprojects:mcp_go_sdk:*:*:*:*:*:*:*:*before 1.4.1VulnerableMLflow
  • cpe:2.3:a:lfprojects:mcp_go_sdk:*:*:*:*:*:*:*:* Versions before 1.4.1 Vulnerable ·MLflow

Remediation

  • Fix · CNA go-sdk (modelcontextprotocol) Fixed in 1.4.1
  • Fix · GHSA-89xv-2j6f-qhc8 github.com/modelcontextprotocol/go-sdk (Go) Fixed in 1.4.1 Advisory →

Red Hat 1 advisory

  • RHSA-2026:21772 Released 2026-05-28 · Red Hat rating Important
    Red Hat OpenShift Dev Spaces 3.28.0 Release.
    • Red Hat OpenShift Dev Spaces 3.28 registry.redhat.io/devspaces/code-rhel9, registry.redhat.io/devspaces/dashboard-rhel9, registry.redhat.io/devspaces/openvsx-rhel9 +3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Migration Toolkit for VirtualizationAffectedNo fix planned: Will not fix
OpenShift ServerlessAffectedNo fix yet
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat OpenShift Dev Spaces 3.28Fixed RHSA-2026:21772
Not affected: 3 products
  • OpenShift Lightspeed
  • Red Hat Hardened Images
  • Red Hat OpenShift Dev Spaces 3.28

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33252
  2. 2026-10-03 Alias added: GHSA-89xv-2j6f-qhc8

References

Patch 2

Advisory 1

Other 1

  • TI-2026-22240 MCP Go SDK Vulnerable to Improper Handling of Case Sensitivity CVSS 4.0HIGH 7.0
  • TI-2026-26986 Model Context Protocol Go SDK: DNS Rebinding Protection Disabled by Default for Servers Running on Localhost CVSS 4.0HIGH 7.6

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences