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CVE-2026-21589 CVSS 7.5

Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

Atlassian — Multiple Products

Added to KEV catalog
15 October 2026
Federal remediation due date
18 October 2026
Weakness classification (CWE)
CWE-552

AI Breakdown

What it is

A security flaw affects multiple Atlassian Data Center and standalone products, including Jira, Confluence, Bitbucket, Crowd, Bamboo, Crucible, and Fisheye. It allows an unauthenticated remote attacker to access specific files located within the web application root directory. To successfully exploit the vulnerability, an attacker must already know the exact file name and path, as it does not allow listing or browsing directory contents.

Why it matters

In certain configurations, exposed files may contain sensitive data that significantly compromises system security. The vulnerability is confirmed to be actively exploited in the wild based on its addition to CISA's catalog, though its use in ransomware campaigns is currently unknown. Unpatched, internet-exposed instances present an immediate risk of unauthorized data exposure.

Recommended action

IT teams must immediately inventory affected Atlassian assets and apply the vendor-released fixed versions. Organizations should evaluate each system's internet exposure and adhere to CISA's BOD 26-04 and forensics triage guidance. If patches cannot be applied right away, implement vendor mitigations or isolate and discontinue the use of affected products.

AI-generated from CISA and NVD data — treat as a starting point, not a substitute for your own risk assessment.

CISA Description

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.

Required action

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.

Notes

https://confluence.atlassian.com/security/cve-2026-21589-arbitrary-file-access-vulnerability-impacts-multiple-products-1870495748.html?ref=labs.watchtowr.com ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-21589

NVD Technical Description

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.

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