CVE entry · CVE-2026-21589

CVE-2026-21589: Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

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.

Actively exploited: added to CISA’s KEV catalog on October 15, 2026.
Use by ransomware: not established so far.
Remediation deadline for US federal agencies: October 18, 2026.

Description from CISA’s KEV catalog.

Our analyses

Cybersecurity

Jira and Confluence flaw that lets anyone read your files without a password is now being exploited

On October 15, the US CISA added CVE-2026-21589, which affects eight Atlassian Data Center products, to its list of exploited flaws. Here are the fixed versions, interim mitigations and traces to look for.

Oct 17, 20262 min read

What to do

Check whether your estate includes affected Atlassian products, including internet-facing devices.
Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.

References

Vendor advisory or reference cited by CISA (confluence.atlassian.com)
NVD entry (NIST)
CISA KEV catalog