WordPress has identified a security vulnerability in versions 5.9 to 6.3.1 that allows malicious attackers with contributor-level privileges or higher to inject malicious scripts into pages that will execute when a user accesses them. This vulnerability is caused by a lack of input sanitization and output escaping when using arrow navigation block attributes. It is important for users of WordPress Core 5.9 to 6.3.1 to update their software as soon as possible to prevent malicious attackers from exploiting this vulnerability.