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

- Exploited (CISA KEV): yes, added 2026-10-15
- Published: 2026-10-05
- CVSS: 9.3 CRITICAL (v4.0)
- EPSS: 99.5% (100th percentile)
- CWE: CWE-552

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.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2026-10-12 | 7 |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Rule published | 2026-10-07 | 2 |
| F5 | Rule published | 2026-10-21 | 16 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2026-10-12 · new · rule 272b2eec72c04313a6f0da2ee919cd31 · default Block
  > Atlassian - Arbitrary File Access - CVE:CVE-2026-21589. Previous action: N/A. New action: Block. This is a new detection.
  Source: https://developers.cloudflare.com/changelog/post/2026-10-12-waf-release/

### Fastly

- 2026-10-07 · new
  > Added virtual patch for CVE-2026-21589 (Pre-Auth Arbitrary File Read in Multiple Atlassian Products). A pre-authorization arbitrary file read vulnerability has been found in multiple Atlassian products (e.g., Confluence, Jira, Bitbucket) and has been assigned CVE-2026-21589. Fastly has created a virtual patch for it that is now available within your account. To activate it and add protection to your services, follow the steps for your control panel below. Next-Gen WAF control panel From the Rul…
  Source: https://www.fastly.com/documentation/reference/changes/2026/10/added-virtual-patch-for-cve-2026-21589/

### F5

- 2026-10-21 · new · rule 200007125
  > Added: signature 200007125 "Atlassian Bitbucket Data Center Arbitrary File Read" (Path Traversal, risk High), systems: Java Servlets/JSP. References: CVE-2026-21589.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: passed (0 of 3 requests blocked), template CVE-2026-21589, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: passed (0 of 3 requests blocked), template CVE-2026-21589, 2026-11-02

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-21589 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-21589