CVE-2026-84425
Received Received - Intake

Denial of Service in CowAgent Browser Tool

Publication date: 2026-09-02

Last updated on: 2026-09-02

Assigner: VulDB

Description
A vulnerability was found in zhayujie CowAgent up to 2.1.3. This impacts the function BrowserTool of the file agent/tools/browser/browser_tool.py of the component Browser Tool. Performing a manipulation results in denial of service. The attack can be initiated remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

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Meta Information

Published
2026-09-02
Last Modified
2026-09-02
Generated
2026-09-02
AI Q&A
2026-09-02
EPSS Evaluated
N/A
NVD
CVE-2026-84425
EUVD
EUVD-2026-69781

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
zhayujie cowagent to 2.1.3 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-404 The product does not release or incorrectly releases a resource before it is made available for re-use.

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Executive Summary

This vulnerability is a denial of service issue in CowAgent up to version 2.1.3. It affects the BrowserTool function in agent/tools/browser/browser_tool.py. The problem occurs because the browser tool uses a shared BrowserService that processes Playwright operations through a single thread. Attackers can exploit this by sending long wait or evaluate operations, causing the thread to block and preventing other browser operations from completing.

Detection Guidance

Monitor for unusually long-running Playwright operations or browser tool processes in CowAgent. Check for blocked browser operations or timeouts in agent logs. Use system monitoring tools to detect high CPU or memory usage from the browser tool process.

Impact Analysis

This vulnerability can make the browser service unavailable by blocking the shared thread with long operations. This prevents normal browser tasks like snapshots or navigation from completing, effectively disrupting the agent's functionality. Attackers can remotely trigger this issue, leading to service disruptions.

Mitigation Strategies

Upgrade CowAgent to a patched version if available. Enforce strict maximum timeouts for browser operations. Disable arbitrary evaluate operations by default. Implement per-user concurrency limits for browser tool usage.

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