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CVE-2026-9739

Published May 27, 2026 CWE-942

Overview

CVE-2026-9739 is a known-severity vulnerability. It was published on May 27, 2026.

Technical Description

Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented `allowed-origins` and `allowed-hosts` flags to align with MCP security guidelines. However, the hardcoded `Access-Control-Allow-Origin: *` header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently Asked Questions

What is CVE-2026-9739?

CVE-2026-9739 is a known-severity vulnerability. It was published on May 27, 2026.

How severe is CVE-2026-9739?

CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.

How do I fix or remediate CVE-2026-9739?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-9739?

CyberStrike's AI-powered security agents can automatically detect CVE-2026-9739 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.