Patch Sonar

Zero-days under active attack, explained in plain English

Newly listed by CISAAtlassian Multiple ProductsDeveloper, data & AI tools

Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

What it is
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's affected
Anyone using Atlassian Multiple Products.
Under attack?
Yes. CISA added this to its catalog of actively exploited vulnerabilities on Oct 15, 2026.
What to do
Install the vendor's security update. If there isn't one yet, apply the vendor's workaround, or stop using the product until it's fixed. CISA lists this as actively exploited, so treat it as urgent.
Fixed in
See the vendor's advisory
CISA deadline
Federal agencies must fix this by Oct 18, 2026. Everyone else should treat that as a ceiling, not a target.
CISA's instruction
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.
CVE-2026-21589Chance of attack in 30 days: 99% (EPSS)Listed Oct 15, 2026Source: CISA catalog ↗

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