CVE record · CVE-2026-21589

Files accessible to external parties in Atlassian Bamboo Data Center and others

CVSS 9.3 CriticalCriticalIn CISA KEVEPSS 1.00 · 99th percentile

Critical, because:

In CISA’s KEV catalogue since 15 Oct 2026: it is known to be exploited.
CVSS score 9.3: 9.0 or more.
CVSS score 9.3 (7.0 or more) and EPSS 1.00 (0.1 or more): a high score and a real chance of exploitation in the next 30 days.

Published by the CVE Program (CNA: atlassian) at 5 Oct 2026, 21:30 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Atlassian	Bamboo Data Center	affected All other versions unaffected Patch version 10.2.24 and later unaffected Patch version 12.1.12 and later
Atlassian	Bitbucket Data Center	affected All other versions unaffected Patch version 10.2.8 and later unaffected Patch version 10.5.1 and later unaffected Patch version 9.4.26 and later
Atlassian	Confluence Data Center	affected All other versions unaffected Patch version 10.2.19 and later unaffected Patch version 9.2.26 and later
Atlassian	Crowd Data Center	affected All other versions unaffected Patch version 7.2.4 and later unaffected Patch version 7.1.7 and later unaffected Patch version 7.0.3 and later unaffected Patch version 6.3.7 and later
Atlassian	Crucible Data Center	affected All other versions unaffected Patch version 4.9.15 and later
Atlassian	Fisheye Data Center	affected All other versions unaffected Patch version 4.9.15 and later
Atlassian	Jira Service Management Data Center	affected All other versions unaffected Patch version 11.3.12 and later unaffected Patch version 10.3.26 and later unaffected Patch version 5.12.40 and later
Atlassian	Jira Software Data Center	affected All other versions unaffected Patch version 11.3.12 and later unaffected Patch version 10.3.26 and later unaffected Patch version 9.12.40 and later

Identifiers: CVE-2026-21589
CNA: atlassian
Weakness (CWE): CWE-552
Tags: Atlassian Bamboo Data Center
Atlassian Bitbucket Data Center
Atlassian Confluence Data Center
Atlassian Crowd Data Center
Atlassian Crucible Data Center
Atlassian Fisheye Data Center
Atlassian Jira Service Management Data Center
Atlassian Jira Software Data Center
Information disclosure
Published: 5 Oct 2026
Updated: 29 Oct 2026

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
9.3	Critical	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H	CNA (atlassian)

CISA KEV Listed since 15 Oct 2026: known to be exploited.
EPSS 1.00, the 99th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 5 Oct 2026. New records show when each source confirmed them.

Sources

References from the CNA

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.