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Actively exploited

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.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 15 Oct 2026.
  • Rated Critical severity (CVSS 9.3, scored by Vendor).
The Vulnerability

What It Is

This is a vulnerability in Bitbucket Data Center, Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Bamboo Data Center. Crowd Data Center, Crucible and Fisheye. This Arbitrary File Access vulnerability allows an unauthenticated attacker to access specific files within the web application root directory in affected versions. Exploitation requires prior knowledge of the target file's exact name and path; this vulnerability does not allow attackers to enumerate or list directory contents. In some configurations, there may be some sensitive files that make this highly severe. This vulnerability allows an unauthenticated remote attacker to access specific files within the web application root directory in affected versions. The vulnerability must be addressed for affected versions of: -- Bitbucket Data Center, introduced in version >= 4.6.0, fix versions: 9.4.26, 10.2.8, 10.5.1 -- Confluence Data Center, introduced in version >= 5.10.0, fix versions 9.2.26, 10.2.19 -- Crowd Data Center, introduced in version >= 2.11.0, fix versions 6.3.7, 7.0.3, 7.1.7, 7.2.4 -- Jira Software Data Center, introduced in version >= 7.1.0, fix versions 9.12.40, 10.3.26, 11.3.12 -- Jira Service Management Data Center, introduced in version >= 3.1.0, fix versions 5.12.40, 10.3.26, 11.3.12 -- Bamboo Data Center >= 7.0.1, fix versions 10.2.24, 12.1.12 -- Crucible, fix versions 4.9.15 -- Fisheye, fix version 4.9.15 -- Exploitation requires prior knowledge of the target file's exact name and path. The vulnerability does not include the capability to enumerate or list directory contents.

Affected Versions

ProductVersions
Atlassian Bamboo Data CenterAll other versions
Atlassian Bitbucket Data CenterAll other versions
Atlassian Confluence Data CenterAll other versions
Atlassian Crowd Data CenterAll other versions
Atlassian Crucible Data CenterAll other versions
Atlassian Fisheye Data CenterAll other versions

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Atlassian Multiple Products. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    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.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 18 Oct 2026 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

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CVE-2021-26086Atlassian Jira Server and Data Center Path Traversal VulnerabilityAdded 12 Nov 2024CVE-2023-22527 · RansomwareAtlassian Confluence Data Center and Server Template Injection VulnerabilityAdded 24 Jan 2024CVE-2023-22518 · RansomwareAtlassian Confluence Data Center and Server Improper Authorization VulnerabilityAdded 7 Nov 2023CVE-2023-22515 · RansomwareAtlassian Confluence Data Center and Server Broken Access Control VulnerabilityAdded 5 Oct 2023CVE-2022-36804Atlassian Bitbucket Server and Data Center Command Injection VulnerabilityAdded 30 Sep 2022CVE-2022-26138Atlassian Questions For Confluence App Hard-coded Credentials VulnerabilityAdded 29 Jul 2022

All 14 exploited Atlassian vulnerabilities

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2026-21589
  3. CVE record: CVE-2026-21589
  4. FIRST EPSS
  5. confluence.atlassian.com/security/cve-2026-21589-arbitrary-file-access-vulnerability-impacts-multipl
  6. jira.atlassian.com/browse/BAM-26567
  7. jira.atlassian.com/browse/BSERV-20604
  8. jira.atlassian.com/browse/CONFSERVER-104488
  9. jira.atlassian.com/browse/CRUC-8741
  10. jira.atlassian.com/browse/CWD-6610
  11. jira.atlassian.com/browse/FE-7583
  12. jira.atlassian.com/browse/JRASERVER-79546