Atlassian Multiple Products Files or Directories Accessible to External Parties
What to do
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.
CISA deadline 2026-10-18 · passed 4 days ago · applies to US federal civilian agencies; used elsewhere as a reference SLA
What happened
Multiple Atlassian products (Bitbucket Data Center ,Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Bamboo Data Center, Crowd Data Center, Crucible and Fisheye) contain a files or directories accessible to external parties vulnerability which could allow an unauthenticated attacker to access specific files within the web application root directory in affected versions.
Who is affected
Atlassian Multiple Products. Affected version ranges are listed in the vendor advisory and the NVD entry linked under Sources.
Weakness class: CWE-552.
Timeline
- Added to CISA KEVExploitation in the wild confirmed by CISA
- CISA remediation deadlinepassed 4 days ago
Sources
- NVD entry for CVE-2026-21589 nvd.nist.gov/vuln/detail/CVE-2026-21589
- CISA Known Exploited Vulnerabilities catalog www.cisa.gov/known-exploited-vulnerabilities-catalog
- confluence.atlassian.com confluence.atlassian.com/security/cve-2026-21589-arbitrary-file-access-vulnerability-impacts-multiple-products-1870495748.html?ref=labs.watchtowr.com
- cisa.gov www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- cisa.gov www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- nvd.nist.gov nvd.nist.gov/vuln/detail/CVE-2026-21589