— Unscored

Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

CVE-2026-21589 Exploited

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.

Being exploited in the wild

Catalogued 15 October 2026 · US federal remediation deadline 18 October 2026

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…

Exploit code is also public: Public PoC · Nuclei template

NucleiAtlassian Jira/Confluence/Bitbucket - Pre-Auth Arbitrary File Read
Public PoCwatchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-2158915 stars
Public PoCtc4dy/CVE-2026-21589-PoC-Exploit11 stars
Public PoCMarcusProgram/CVE-2026-215899 stars
Public PoCynsmroztas/AtlasSniper7 stars
Public PoCmurrez/CVE-2026-215891 stars
Public PoCgotr00t0day/CVE-2026-215891 stars
Public PoCaduli198/CVE-2026-21589
Public PoCBimBoxH4/CVE-2026-21589

Assessment

CVSS: Not yet scored
Severity: Unscored
Known exploited: Yes — listed in the CISA KEV catalog
Exploit availability: CISA KEV, Public PoC, Nuclei template
Published: 15 October 2026
Last updated: 15 October 2026
Affected: Atlassian · Multiple Products
Weakness: CWE-552

At the source

CISA KEV

References

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

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