CVE-2026-21589: Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

Atlassian · Multiple Products

Listed by CISA as exploited in the wild since 15 Oct 2026. Below: exploitation status, EPSS and every published CVSS, each with its source, then affected versions and references.

Build snapshot collected 22 Oct 2026, 06:56 UTC · KEV catalog 2026.10.21 · EPSS of 21 Oct 2026 · not a live feed: collected once, at build time

Description

as written by CISA (KEV catalog)

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 affected versions.

Required action

CISA KEV

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.

Affected products and versions

CVE record · atlassian

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

Status words (affected, unaffected, unknown) and version bounds are copied from the record. An upper bound such as “before 7.1.0” usually marks the first fixed version; confirm in the vendor advisory before planning an upgrade.

References

CISA KEV notes and CVE record

EPSS over the last 30 days

Added in the same week (see the week)

Questions about CVE-2026-21589

Is CVE-2026-21589 being exploited?

Yes, according to CISA. CVE-2026-21589 was added to the Known Exploited Vulnerabilities catalog on 15 Oct 2026, which CISA does only with reliable evidence of exploitation in the wild. The catalog field for ransomware campaign use says "Unknown".

What is the deadline to remediate CVE-2026-21589?

CISA set 18 Oct 2026 as the due date for US Federal Civilian Executive Branch agencies. The date is binding only for those agencies; other organisations can read it as a measure of urgency.

What is the EPSS score of CVE-2026-21589?

12.7%, in the 96th percentile, in the FIRST EPSS model of 21 Oct 2026. It estimates the probability of exploitation activity in the following 30 days. For a CVE already in KEV the score is secondary: exploitation has been observed.

How severe is CVE-2026-21589?

atlassian rates it 9.3 CRITICAL (CVSS 4.0). These are the published assessments as of 22 Oct 2026; this site does not rescore.

Which product does CVE-2026-21589 affect?

Atlassian Multiple Products, as named in the CISA catalog. The affected versions listed in the CVE record are on this page; the vendor advisory in the references is the authority on fixed versions.