CVE-2026-21589

CRITICAL CVSS 4.0: 9.3 EPSS 12.7% ACTIVE EXPLOIT
Updated Oct 19, 2026
Bitbucket

CISA Known Exploited Vulnerability (KEV)

This vulnerability is actively exploited in the wild. Immediate patching is strongly recommended.

Due Date: Oct 18, 2026

Parameter Value
CVSS 9.3 (CRITICAL)
Affected Versions 10.3.0 — 9.4.26
Fixed In 9.4.26
Type CWE-552
Vendor Bitbucket
Public PoC Yes

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 21

Configuration From (including) Up to (excluding)
Atlassian Bitbucket_Data_Center
cpe:2.3:a:atlassian:bitbucket_data_center:*:*:*:*:*:*:*:*
7.17.0 9.4.26
Atlassian Bitbucket_Data_Center
cpe:2.3:a:atlassian:bitbucket_data_center:*:*:*:*:*:*:*:*
9.5.0 10.2.8
Atlassian Bitbucket_Data_Center
cpe:2.3:a:atlassian:bitbucket_data_center:*:*:*:*:*:*:*:*
10.3.0 10.5.1
Atlassian Bitbucket_Server
cpe:2.3:a:atlassian:bitbucket_server:*:*:*:*:*:*:*:*
4.6.0 <= 8.14.6
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
5.10.0 9.2.26
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
9.3.0 10.2.19
Atlassian Crowd
cpe:2.3:a:atlassian:crowd:*:*:*:*:*:*:*:*
2.11.0 6.3.7
Atlassian Crowd
cpe:2.3:a:atlassian:crowd:*:*:*:*:*:*:*:*
7.0.0 7.0.3
Atlassian Crowd
cpe:2.3:a:atlassian:crowd:*:*:*:*:*:*:*:*
7.1.0 7.1.7
Atlassian Crowd
cpe:2.3:a:atlassian:crowd:*:*:*:*:*:*:*:*
7.2.0 7.2.4
Atlassian Jira_Data_Center
cpe:2.3:a:atlassian:jira_data_center:*:*:*:*:*:*:*:*
7.1.0 9.12.40
Atlassian Jira_Data_Center
cpe:2.3:a:atlassian:jira_data_center:*:*:*:*:*:*:*:*
9.13.0 10.3.26
Atlassian Jira_Data_Center
cpe:2.3:a:atlassian:jira_data_center:*:*:*:*:*:*:*:*
10.4.0 11.3.12
Atlassian Jira_Service_Management
cpe:2.3:a:atlassian:jira_service_management:*:*:*:*:data_center:*:*:*
3.1.0 5.12.40
Atlassian Jira_Service_Management
cpe:2.3:a:atlassian:jira_service_management:*:*:*:*:data_center:*:*:*
5.13.0 10.3.26
Atlassian Jira_Service_Management
cpe:2.3:a:atlassian:jira_service_management:*:*:*:*:data_center:*:*:*
10.4.0 11.3.12
Atlassian Bamboo
cpe:2.3:a:atlassian:bamboo:*:*:*:*:*:*:*:*
7.0.1 10.2.24
Atlassian Bamboo
cpe:2.3:a:atlassian:bamboo:*:*:*:*:*:*:*:*
11.0.0 12.1.12
Atlassian Crucible
cpe:2.3:a:atlassian:crucible:*:*:*:*:*:*:*:*
— 4.9.15
Atlassian Fisheye
cpe:2.3:a:atlassian:fisheye:*:*:*:*:*:*:*:*
— 4.9.15
Atlassian Jira_Service_Desk
cpe:2.3:a:atlassian:jira_service_desk:*:*:*:*:data_center:*:*:*
3.1.0 <= 4.13.27