Artificial Intelligence

Claude Code sent your email in User-Agent

Claude Code leaked user emails in User-Agent headers during web searches; Anthropic's fix is cc-plugin-privacy, a toggle in /plugins enabled by default in v2.1.317.

StartupHub.ai Staff

By StartupHub.ai Staff, reviewed by Daniel Singer, Editor

2 min read

Code terminal showing User-Agent header with email address
Credit: GitHub

The privacy guarantee for GitHub issue #107757 lives as a toggle in /plugins where Anthropic says cc-plugin-privacy ships enabled by default in v2.1.317 and can be turned off.

Reporter taylor-edwards said Claude Code inserted his email into the User-Agent header while conducting web searches on darwin with version 2.1.318 in tmux, sending it to arbitrary third parties without permission and without any remote attacker, only a normal search prompt.

Contributor poteat explained the model was handed the user's email in context and, when asked to research a site like Wikipedia whose policy asks scripted clients to identify via User-Agent contact email, the agent built a curl with that email in the header.

Anthropic says the built-in cc-plugin-privacy deterministically blocks that substitution and is source available for audit, while daily.dev notes the mod is intended to block personal data like email addresses in request headers generally and is enabled by default though it can be disabled via /plugins, and reporter francescor on v2.1.318 said he could not see it in /plugins.

Commenters argued the fix is a bandaid because the harness still preloads the email into context by default, so privacy remains a plugin rather than an invariant and any gap in checks again exposes the address to any site the agent fetches.

Until the email is no longer in context by default, verify cc-plugin-privacy is present and enabled in /plugins, pin allowed User-Agent emails to approved domains like wikipedia.org in CLAUDE.md as user xSetech did, and consider firewalling agent traffic or using an alternative harness like pi where users report no leak.

Sources

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TopicsAnthropicClaude Codecc-plugin-privacyUser-AgentGitHubWikipediaOpenRouter

StartupHub.ai Staff

Written by

StartupHub.ai Staff

Editorial team

The staff writers of StartupHub.ai, ranging from investment analysts to avid AI tool users, early adopters and critical enthusiasts. Backgrounds span engineering, business and the arts. We hold every piece to rigorous standards of research and review.

Daniel Singer

Written by

Daniel Singer

Editor, reviewed this article

Daniel Singer is an AI expert who has been writing about, covering and building AI technology since 2018.

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