What is the Attack? CVE-2026-21589 is a critical arbitrary file access vulnerability affecting multiple Atlassian Data Center and Server products. It allows an unauthenticated remote attacker to access specific files within an affected application's web root, provided the attacker knows the exact file path and name. The vulnerability stems from improper restrictions on access to files within the web application root. Successful exploitation could expose sensitive files and potentially provide information useful for further attacks, depending on the affected application's configuration and the files accessible. The vulnerability requires no authentication or user interaction, making internet-