PromptSnatcher Ad Blocker Extensions Steal AI Chats From ChatGPT, Claude, and Gemini

Cybersecuritynews •Tushar Subhra Dutta • June 15, 2026

Two browser extensions masquerading as ad blockers have been caught secretly recording private conversations from ChatGPT, Claude, Gemini, and five other major AI platforms. The extensions, named “Smart Adblocker” and “Adblock for Browser,” were installed by roughly 90,000 users before the scheme was uncovered. Users genuinely received ad-blocking functionality while their most sensitive AI conversations […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

PromptSnatcher: Ad Blocker Extensions Compromise AI Chat Privacy Two Chrome extensions, 'Smart Adblocker' and 'Adblock for Browser', have been discovered to exfiltrate user prompts and responses from major AI platforms including ChatGPT, Claude, and Gemini. These extensions, masquerading as ad blockers, were installed by approximately 90,000 users. They intercept communications and send data to operator-controlled servers while also checking if users are paid subscribers on five of the eight targeted platforms. The malicious extensions share the same capture engine and payload format. Reports have been filed regarding their abuse on the Chrome Web Store, and a detailed analysis of the indicators of compromise (IOCs) has been released. The situation remains active as users are urged to remove the extensions immediately. 3 sources 69

PromptSnatcher Ad Blocker Extensions Steal AI Chats From ChatGPT, Claude, and Gemini

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