What happened
Published Aug 30, 2026 with CVSS 5.5 (Medium). browser-use is a popular open-source agentic browser-automation framework that lets LLM agents drive a real browser; its bundled web UI persists user-supplied LLM credentials insecurely.
Why it matters
browser-use is a widely-adopted computer-use/browser-use agent framework; leaked LLM API keys allow an attacker to run up billing on the victim's account, exfiltrate data processed by the agent, or pivot into any other systems the same API key is scoped to access.
Attack vector
browser-use web-ui writes configured LLM API keys (OpenAI, Anthropic, etc.) to disk in cleartext, in predictably-named JSON files under a temporary settings directory, without encryption or access restriction. Any attacker or process with local read access to that directory can recover the provider API keys.
Affected systems
browser-use/web-ui versions 2.0.0 through 3.0.0
Mitigation
Upgrade to a patched version when available; avoid storing provider API keys via the affected settings mechanism; rotate any API keys that may have been exposed on shared or multi-tenant hosts; restrict filesystem permissions on the settings directory.