CVE-2026-21589

CVE-2026-21589: Critical unauthenticated arbitrary file access in Atlassian products

Published Oct 5, 2026 · corrected/updated Oct 16, 2026 · Atlassian Multiple Products · evidence confidence very high

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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-21589 is a critical public vulnerability record for Atlassian Multiple Products. CISA lists it as known exploited. Published remediation guidance: 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. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Atlassian Multiple Products is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: atlassian/bamboo; atlassian/bitbucket data center; atlassian/bitbucket server; atlassian/confluence data center. Published remediation guidance: 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. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 9.3, EPSS 278.0%. CISA lists it as known exploited. Weakness classes: CWE-552. Sources contributing to this record: canada, cisa_kev, cve_org, epss. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

Exploitation evidence
Confirmed in CISA KEV since Oct 7, 2026. Listed in CISA KEV and VulnCheck KEV.
Patch and remediation
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.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

Oct 7, 2026 · Rapid7 Vulnerability Database
Detected
Overview On October 5, 2026, Atlassian published a security advisory for CVE-2026-21589 , a critical arbitrary file access vulnerability affecting eight 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. Atlassian assigned the vulnerability a CVSSv4 score of 9.3 . An
Oct 14, 2026 · NIST NVD
Updated
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 knowledg
Oct 15, 2026 · CISA KEV
Known exploited
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
Oct 15, 2026 · NIST NVD
Updated
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 knowledg
Oct 15, 2026 · NIST NVD
Updated
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 knowledg
Oct 16, 2026 · NIST NVD
Updated
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 knowledg
Oct 16, 2026 · EUVD
Updated
This CVE's publication may have been a false positive or a mistake. As a result, we have rejected this record.
Oct 18, 2026 · CISA KEV
Remediation due
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

Affected

cpe atlassian/bambooversion unspecified
cpe atlassian/bitbucket data centerversion unspecified
cpe atlassian/bitbucket serverversion unspecified
cpe atlassian/confluence data centerversion unspecified
cpe atlassian/crowdversion unspecified
cpe atlassian/crucibleversion unspecified
cpe atlassian/jira data centerversion unspecified
cpe atlassian/jira service managementversion unspecified
vendor Atlassian Multiple Productsversion unspecified
vendor atlassianversion unspecified

Sources

Canadian Centre for Cyber SecurityGovernment advisoryCVE-2026-21589
Serial number: AV26-1002 Date: October 5, 2026 Updated: October 15, 2026 As of October 5, 2026, Atlassian is affected by a vulnerability in the following products: Bamboo Data Center Version 10.2.4 and prior Version 12.1.12 and prior Bamboo Server All versions Bitbucket Data Cent
cyber.gc.ca
CISA KEVConfirmed exploitationCVE-2026-21589
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 affecte
cisa.gov
CVE.orgVulnerability recordCVE-2026-21589
Official CVE identifier
cve.org
FIRST EPSSExploitation probabilityCVE-2026-21589
30-day exploitation probability 12.7%
first.org
EUVDVulnerability recordEUVD-2026-92807
This CVE's publication may have been a false positive or a mistake. As a result, we have rejected this record.
euvd.enisa.europa.eu
NIST NVDVulnerability recordCVE-2026-21589
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 ac
nvd.nist.gov
Rapid7 Vulnerability DatabaseResearchCVE-2026-21589
Overview On October 5, 2026, Atlassian published a security advisory for CVE-2026-21589 , a critical arbitrary file access vulnerability affecting eight 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. Atlassian assigned the vulnerability a CVSSv4 score of 9.3 . An
rapid7.com
VulnCheck KEVConfirmed exploitationCVE-2026-21589
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 whi
vulncheck.com