CVE-2026-21589

HighActively exploited (CISA KEV)

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.

SeverityHigh
CVSS7.5
Exploit probability—
ProductAtlassian Multiple Products
PublishedOct 5, 2026
First seenOct 5, 2026
Added to KEVOct 15, 2026
Weakness typeCWE-552CWE-552

How to fix

CISA 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.

CISA due date: Oct 18, 2026
Update
  • atlassian bitbucket_data_center9.4.26, 10.2.8, 10.5.1 or later
  • atlassian confluence_data_center9.2.26, 10.2.19 or later
  • atlassian crowd6.3.7, 7.0.3, 7.1.7, 7.2.4 or later
  • atlassian jira_data_center9.12.40, 10.3.26, 11.3.12 or later
  • atlassian jira_service_management5.12.40, 10.3.26, 11.3.12 or later
  • atlassian bamboo10.2.24, 12.1.12 or later
  • atlassian crucible4.9.15 or later
  • atlassian fisheye4.9.15 or later

Affected products

ProductAffected versionsFixed in
atlassian bitbucket_data_center7.17.0 ≤ v < 9.4.26, 9.5.0 ≤ v < 10.2.8, 10.3.0 ≤ v < 10.5.19.4.26, 10.2.8, 10.5.1
atlassian bitbucket_server4.6.0 ≤ v ≤ 8.14.6—
atlassian confluence_data_center5.10.0 ≤ v < 9.2.26, 9.3.0 ≤ v < 10.2.199.2.26, 10.2.19
atlassian crowd2.11.0 ≤ v < 6.3.7, 7.0.0 ≤ v < 7.0.3, 7.1.0 ≤ v < 7.1.7, 7.2.0 ≤ v < 7.2.46.3.7, 7.0.3, 7.1.7, 7.2.4
atlassian jira_data_center7.1.0 ≤ v < 9.12.40, 9.13.0 ≤ v < 10.3.26, 10.4.0 ≤ v < 11.3.129.12.40, 10.3.26, 11.3.12
atlassian jira_service_desk3.1.0 ≤ v ≤ 4.13.27—
atlassian jira_service_management4.14.0 ≤ v < 5.12.40, 5.13.0 ≤ v < 10.3.26, 10.4.0 ≤ v < 11.3.125.12.40, 10.3.26, 11.3.12
atlassian bamboo7.0.1 ≤ v < 10.2.24, 11.0.0 ≤ v < 12.1.1210.2.24, 12.1.12
atlassian cruciblev < 4.9.154.9.15
atlassian fisheyev < 4.9.154.9.15

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CVE-2026-21589 · Atlassian Multiple Products · Dark Radar