Spammers have repurposed "ASCII smuggling," a technique originally designed to facilitate stealthy prompt injection attacks against Large Language Models (LLMs), to bypass email security filters. This method utilizes a specific block of 128 Unicode tags—such as U+E0041 for "A" and U+E0061 for "a"—to encode text. These characters are processed and readable by computer algorithms but remain virtually invisible to human readers. While LLMs can decode these tags to execute hidden instructions, email detectors often fail to recognize the obfuscated keywords. Microsoft Defender for Office reported a massive surge in this activity in early February, where daily detections of ASCII smuggling signatures spiked from approximately 21,000 to over 1.3 million. This trend escalated further within four days, reaching 2.5 million daily detections. This wave of obfuscated spam persisted for several months before declining significantly in mid-May. By leveraging the discrepancy between human perception and machine-level text processing, attackers can deliver mass campaigns that evade keyword-based detection while remaining undetected by the recipients.