Researcher Says Claude Desktop Installs Browser Bridge Without User Notice
Summary
Alexander Hanff reports that Claude Desktop installs a persistent native-messaging bridge that preauthorizes browser extensions. He warns it could expose authenticated sessions; the article says no official response has been issued.
Key points
- Hanff says Claude Desktop autonomously creates a JSON manifest in Brave that preauthorizes three extension IDs to invoke a local executable.
- The bridge can enable browser automation, DOM and console access, form filling, structured data extraction, and session recording, according to documentation cited in the article.
- Hanff says the manifest persists across seven Chromium-based browsers and is rewritten when Claude Desktop launches, without notification or an opt-out.
- The article warns that malicious extensions or prompt injection could potentially abuse the bridge to access authenticated sessions and exfiltrate data; it does not report a confirmed abuse.
- The article says no official response had been issued at publication.
Article Details
- Event Type
- Reported privacy and security risk from Claude Desktop's installation of a persistent native messaging bridge for Chromium-based browsers.
- Impact
- The bridge reportedly pre-authorizes browser extensions to communicate with local executables and access browser capabilities, including authenticated sessions, page content, and session recording, without user notification or an opt-out. The article says a malicious extension or prompt injection could potentially abuse it for surveillance and data exfiltration. The manifest is reportedly rewritten on launch and can only be removed by uninstalling Claude Desktop. No official response had been issued at the time of the article.
People
Products
BraveA JSON manifest was auto-created in Brave pre-authorizing three extension IDs to invoke a localhost executable.Claude DesktopAlexander Hanff found that Claude Desktop silently installs a native messaging bridge that pre-authorizes browser extensions to communicate with local executables, enabling browser automation, DOM access, session
Industries
BankingIf abused via prompt injection or malicious extensions, the component could expose authenticated banking, healthcare, and corporate sessions and enable data exfiltration.HealthcareIf abused via prompt injection or malicious extensions, the component could expose authenticated banking, healthcare, and corporate sessions and enable data exfiltration.