Patch Forecast
Red warning
Act within 24 hours. CISA deadline for US federal agencies: 18 Oct 2026.

CVE-2026-21589 Exploited in the wild

Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability

Risk score
99/100
CVSS
7.5 v3.1
Exploit chance (30 days)
12.7%
Published
5 Oct 2026
Added to CISA's exploited list
15 Oct 2026

Open in the live forecast Today's forecast

What to know

What it is
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 appl…
Affected
Atlassian Multiple Products
Fix
Apply the vendor's security update; see the linked advisory.
Exploitation
Exploited in the wild

In the news

TL;DR

Atlassian patches 75 vulnerabilities in multiple products, including CVE-2026-21589, a high-severity Arbitrary File Access vulnerability.

  • CVE-2026-21589 is a high-severity vulnerability (CVSS 7.5) in Bitbucket Data Center, Confluence Data Center, and other Atlassian products.
  • The vulnerability allows an unauthenticated attacker to access specific files within the web application root directory.
  • Atlassian has patched the vulnerability, and users are advised to update to the latest product versions or fixed releases.
  • SecurityWeek reports that Atlassian makes no mention of any of the vulnerabilities being exploited in attacks.

AI summary of 1 article.

Why it is Red

  • CVSS 7.5 high
  • Exploitation likely: EPSS 12.7% (top 4%)
  • Exploited in the wild (CISA KEV)
  • Remotely exploitable without logging in

CISA 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.

References

Original description

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.

Last activity 15 Oct 2026. Patch Forecast updates every hour.