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VulnerabilitiesAug 5, 2026

CSS: The Hidden Threat Lurking in Your Inbox

CSS can now exfiltrate data from webmail, researchers warn.

Summary

Researchers have discovered that Cascading Style Sheets (CSS), traditionally used for web design, can now be exploited to exfiltrate sensitive data from webmail clients. This technique leverages CSS features to leak information, posing a significant threat to user privacy and data security. Some webmail vendors are reportedly unprepared for this emerging attack vector.

Entities

CSS (technology)