Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability (CVE-2026-21589) is being actively exploited, CISA warns

Treat this as an emergency. Identify every system running Confluence & Jira, apply the vendor's fix or published mitigations immediately, and check for signs of compromise. Patching alone does not remove an attacker who already got in.

CISA's required action for CVE-2026-21589: "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines." US federal civilian agencies must comply by October 18, 2026.