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Vulnerabilities

Vulnerability · CVE-2026-33252

The Go MCP SDK used Go's standard encoding/json.

Published Mar 24, 2026 · catalog updated Jun 17, 2026 · mcp go sdk

Check if you run it

No confirmed exploitation is on record for CVE-2026-33252. EPSS is 0.21%. Act only if a listed version of mcp go sdk is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.21%
Remediation
Advisory link
Affected products
cpe lfprojects/mcp go sdk

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 requests without validating the header and without requiring . 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe lfprojects/mcp go sdkversion unspecified

How to fix CVE-2026-33252

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-33252. EPSS is 0.21%. Act only if a listed version of mcp go sdk is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-352: Cross-Site Request Forgery (CSRF). EPSS 0.21%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 24, 2026 · NIST NVD

    Detected

    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 requests without validating the header and without requiring . 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 t

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 requests without validating the header and without requiring . 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 t

Sources

  • CVE.orgVulnerability recordCVE-2026-33252

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33252

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33252

    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 requests without validating the header and without requiring . In deployments with

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.