Missing Origin Validation in Google Agent Development Kit WebSockets
CVE-2026-107858

7.2HIGH

Key Information:

Vendor: Google
Status: Agent Development Kit (adk) For Java
Vendor: CVE Published:; 23 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-107858?

The Google Agent Development Kit (ADK) has a significant vulnerability due to missing origin validation in WebSockets and a permissive cross-domain policy. This flaw allows unauthorized remote access by an attacker to a locally running agent on the developer's machine through a malicious web page. Versions 0.1.0 to 1.12.0 of the ADK's WebSocket endpoint accept connections from any origin, thus enabling an attacker to send messages to the agent, triggering unwanted actions, and gaining control over sensitive data. While a mitigation measure is available by configuring an allowlist of trusted origins in versions 1.6.0 to 1.12.0, the issue is fully resolved in version 1.13.0, which enforces strict same-origin policies.

Affected Version(s)

Agent Development Kit (ADK) for Java 0.1.0 < 1.13.0

Agent Development Kit (ADK) for Java 0.3.0 < 1.13.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-107858 - Proof of Concept