CVE-2026-33252
Description
A flaw was found in the Go MCP SDK's Streamable HTTP transport, which uses Go's standard encoding/json package. In deployments without authorization, a remote attacker can exploit this Cross-Site Request Forgery (CSRF) vulnerability. By sending browser-generated cross-site POST requests to a local server without proper validation of the Origin header or Content-Type, an attacker can potentially trigger unauthorized tool execution.
Mitigation
To mitigate this vulnerability, ensure that deployments utilizing the Go MCP SDK are configured with proper authorization mechanisms. This prevents unauthorized cross-site requests from triggering tool execution. Additionally, restrict network access to the local server running the SDK to trusted sources only, using firewall rules to limit exposure.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.1 | 6.5 | 7.1 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | High | High | High |
| Availability Impact | Low | None | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context; Bypass Protection Mechanism
An attacker can access any functionality that is inadvertently accessible to the source.
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