Researchers at Adversa AI discovered that Grok can be tricked into decrypting and executing hidden malicious instructions embedded in AES-256-GCM encrypted webpage content. When asked to summarize a page with encrypted payloads, Grok decrypts them within its code execution environment, bypassing content filters that cannot read strong encryption. In proof-of-concept tests, the attack achieved a 40% success rate and leaked users’ full names, locations, subscription tiers, and complete chat histories.
The vulnerability is architectural: content filters operate before execution and cannot decrypt strong ciphers, so decryption becomes a trust bypass. OpenAI’s GPT-5 rejected the payloads, and Anthropic’s Claude flagged the injection after decrypting. This is Grok-specific.
xAI was notified on June 3 through HackerOne and has not patched it as of August. Two and a half months of full exploitability, with no comment from the company.
Sources: Zero-click Grok data theft: Cryptographic Context Injection attack leaks chat histories
Coverage: New Cryptographic Context Injection Attack Could Let Web Pages Steal Grok Chat Data • Grok chat duped into swallowing injected instructions
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