Is CVE-2026-34742 actively exploited?

No active exploitation of CVE-2026-34742 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-34742 be exploited remotely?

Yes. CVE-2026-34742 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-34742?

CVE-2026-34742 has a CVSS score of 8.1 (HIGH).

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HIGH

CVE-2026-34742

CWE-1188Published: April 2, 2026· Updated: Apr 3, 2026

8.1

CVSS v3.1

EPSS:0.05%probability of exploitation in 30 daysPercentile:16.2th

Official Description

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.0, the Model Context Protocol (MCP) Go SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPHandler or SSEHandler, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. This issue has been patched in version 1.4.0.

NVD Source

Technical Analysis

CVE-2026-34742 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 8.1.