CVE-2026-21589
7.5 · HIGHActively ExploitedThis is a vulnerability in Bitbucket Data Center, Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Bamboo Data Center.
Overview
CVE-2026-21589 is a high-severity vulnerability affecting atlassian bitbucket_data_center. It was published on October 5, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
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
Remediation
Check the references section for vendor advisories and patches from atlassian. Update bitbucket_data_center to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| atlassian | bitbucket_data_center | >= 7.17.0, < 9.4.26 | Affected |
| atlassian | bitbucket_server | 4.6.0 | Affected |
| atlassian | confluence_data_center | >= 5.10.0, < 9.2.26 | Affected |
| atlassian | crowd | >= 2.11.0, < 6.3.7 | Affected |
| atlassian | jira_data_center | >= 7.1.0, < 9.12.40 | Affected |
| atlassian | jira_service_desk | 3.1.0 | Affected |
| atlassian | jira_service_management | >= 4.14.0, < 5.12.40 | Affected |
| atlassian | bamboo | >= 7.0.1, < 10.2.24 | Affected |
| atlassian | crucible | >= 0, < 4.9.15 | Affected |
| atlassian | fisheye | >= 0, < 4.9.15 | Affected |
References
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Frequently asked questions
What is CVE-2026-21589?
CVE-2026-21589 is a high-severity vulnerability affecting atlassian bitbucket_data_center. It was published on October 5, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
How severe is CVE-2026-21589?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-21589?
Check the references section for vendor advisories and patches from atlassian. Update bitbucket_data_center to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21589?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-21589 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.
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