Gemini Has a Known Vulnerability — and Google Is Leaving It Alone

Google’s Gemini AI has recently come under scrutiny after cybersecurity researcher Viktor Markopoulos from FireTail revealed a new exploit technique called “ASCII smuggling.” This attack method exposes a subtle yet powerful flaw in how AI models interpret text input — and surprisingly, Google has decided not to fix it.

Hidden Commands in Plain Text

The vulnerability works by embedding invisible characters in text — control codes or Unicode symbols — that humans cannot see but which the AI still processes as commands. These hidden instructions can change how Gemini behaves, potentially altering or fabricating information without the user’s knowledge.

For example, a simple email or calendar invite may look harmless but could secretly contain instructions that cause Gemini to rewrite meeting details, distort summaries, or leak sensitive data. Since these control characters are invisible, even a trained eye wouldn’t easily spot them.

Other AI Models Handle It Better

Markopoulos tested the same ASCII smuggling technique across various AI systems, including OpenAI’s ChatGPT, Anthropic’s Claude, and Microsoft’s Copilot. Those platforms either filtered or sanitized the hidden characters before processing the text.

However, Gemini — along with Elon Musk’s Grok and China’s DeepSeek — failed to block or recognize the exploit. This finding raises questions about Google’s input validation and its approach to prompt safety, especially since Gemini is designed to integrate deeply with Google Workspace, Gmail, and Calendar.

Google’s Official Response: It’s Not a Bug

In its response to FireTail’s report, Google classified ASCII smuggling as a “social engineering issue” rather than a technical vulnerability. In other words, Google argues the problem arises from users being manipulated into providing malicious input — not from Gemini’s underlying architecture.

This stance effectively shifts the responsibility away from system-level security. However, cybersecurity experts warn that such a distinction may not hold up in real-world scenarios, where attackers routinely exploit the differences between human perception and machine interpretation.

Why This Matters

The biggest concern is that Gemini’s role extends beyond casual chat. As Google integrates it across Docs, Gmail, Sheets, and Calendar, the potential for data corruption or miscommunication grows. A cleverly crafted message could trick Gemini into summarizing false information or modifying records inside a corporate workflow.

Since these systems often process sensitive business data, the risk isn’t just theoretical — it could have serious implications for data integrity and enterprise security. While Google’s decision to dismiss this flaw as “social engineering” may simplify its response, it leaves room for potential misuse that other AI companies have already mitigated.

Past Fixes and the Gemini Trifecta

Interestingly, Google has fixed other vulnerabilities in Gemini earlier this year, such as the so-called “Gemini Trifecta” — a trio of flaws found in logs, search summaries, and browsing histories. Those issues involved data leakage and unintended cross-session memory retention, all of which Google promptly addressed.

However, the ASCII smuggling exploit remains unresolved. Given the pace at which attackers innovate, ignoring it could prove shortsighted, especially as Gemini continues to expand its footprint across consumer and enterprise ecosystems.

Conclusion

Gemini’s ASCII smuggling flaw highlights a broader challenge in AI security: machines read text differently from humans. The invisible gap between perception and interpretation can be exploited — and companies that underestimate that gap risk turning minor quirks into major vulnerabilities.

While Google may see this issue as low priority, the rest of the cybersecurity community is watching closely. As AI becomes more integrated with everyday communication, even invisible characters could have visible consequences.

In short: Gemini’s flaw might be hidden, but its implications are not.