>>105585232>The bug stems from unsanitized $_GET['_from'] input, enabling PHP object deserialization and session corruption when session keys begin with an exclamation mark.>The flaw, which impacts Roundcube versions 1.1.0 through 1.6.10, spanning over a decade>Shortly after the patch was released, hackers reverse-engineered it to develop a working exploit, which they sold on underground forums.https://www.bleepingcomputer.com/news/security/over-84-000-roundcube-instances-vulnerable-to-actively-exploited-flaw/