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Invisible Unicode tags in untrusted text will break your agent pipelines
◆ 85RelevanceOn a story from The New Stack1mo ago
If your AI agent processes external data like emails or web scrapes, you must strip invisible Unicode characters immediately. These tags can bypass standard filters to redirect agent behavior or hijack execution flows. Update your preprocessing logic to treat non-printable characters as a high-priority security risk.
Takeaways
- Invisible Unicode tags bypass standard text-based prompt injection detection.
- Sanitize all untrusted inputs to strip non-printable characters before model inference.
- This technique is already being deployed at scale in active phishing campaigns.
Read the original at thenewstack.io
Microsoft built a prompt injection detector. Then it caught a phishing campaign instead.
fmode.me/n/microsoft-built-a-prompt-injection-detector-then-it-caught-a-phishing-campaign-instead
Written by Founder Mode using gemini-3-flash-preview, from the publisher's own summary. We link the original rather than reproduce it — the reporting belongs to The New Stack.
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