Exploited vulnerabilities / CVE-2026-21589
Confirmed exploited · exploited vulnerability · Atlassian Multiple ProductsCVE-2026-21589
Atlassian Multiple Products exploited vulnerability, confirmed exploited in the wild.
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.
| CISA's name for it | Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability |
|---|---|
| Vendor and product | Atlassian · Multiple Products |
| Type | exploited vulnerability · CWE-552 |
| Exploited | Confirmed by CISA listed 15 October 2026 |
| Likelihood | one of the most likely to be exploited of every vulnerability tracked |
| Deadline | 18 October 2026 · already passed |
| Used in ransomware | Not reported |
| Advisories | confluence.atlassian.com ↗ · www.cisa.gov ↗ · www.cisa.gov ↗ · nvd.nist.gov ↗ |
Three steps, in this order
Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited.
If you cannot patch now, restrict network access to the affected product.
Check for signs of compromise since the date it was added to the list.
| CISA's required action | 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. |
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Know before someone else finds it
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CVE-2026-21589 in short
Is CVE-2026-21589 being exploited?
Yes. CISA added CVE-2026-21589 to its Known Exploited Vulnerabilities catalogue on 15 October 2026, which it does only on evidence of exploitation in the wild.
What is the CISA deadline for CVE-2026-21589?
US federal agencies must remediate it by 18 October 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.
How likely is CVE-2026-21589 to be exploited in the next 30 days?
FIRST's Exploit Prediction Scoring System gives it 100%, the 99th percentile of every CVE it scores.
How do I fix CVE-2026-21589?
Apply the vendor's fix or mitigation; CISA lists only vulnerabilities seen exploited. If you cannot patch now, restrict network access to the affected product. Check for signs of compromise since the date it was added to the list.
Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.