---
title: "CVE-2026-21589: Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-21589/
description: "CVE-2026-21589 (Atlassian Multiple Products): Exploited in the wild (CISA KEV). This is a vulnerability in Bitbucket Data Center, Confluence Data Center…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-05
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-21589"
kev: true
cvss: 9.3
epss: 0.12711
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Atlassian Multiple Products. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-10-15, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-10-18 ; treat that as the outer limit, not the target.
- EPSS 12.7% , percentile 96: FIRST’s model estimates a 12.7% chance of exploitation activity in the next 30 days, higher than 96% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Act now. Atlassian Data Center File Read CVE-2026-21589 Exploited — Every self-managed Atlassian Data Center product is affected, a public detection script exists and CISA confirms exploitation; patch to a fixed LTS or block traversal patterns at the edge today.

## 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 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.

## Affected products (CVE record)

- Atlassian Bamboo Data Center: All other versions
- Atlassian Bitbucket Data Center: All other versions
- Atlassian Confluence Data Center: All other versions
- Atlassian Crowd Data Center: All other versions
- Atlassian Crucible Data Center: All other versions
- Atlassian Fisheye Data Center: All other versions
- Atlassian Jira Service Management Data Center: All other versions
- Atlassian Jira Software Data Center: All other versions

## Severity

- atlassian CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:H`

## Exploitation

- CISA KEV: added 2026-10-15; federal due date 2026-10-18. Known ransomware use: Unknown.
- 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.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 12.71% probability of exploitation activity in the next 30 days; percentile 96.

## Sources

- [Listed in CISA KEV notes (confluence.atlassian.com)](https://confluence.atlassian.com/security/cve-2026-21589-arbitrary-file-access-vulnerability-impacts-multiple-products-1870495748.html?ref=labs.watchtowr.com)
- [CVE.org record CVE-2026-21589](https://www.cve.org/CVERecord?id=CVE-2026-21589)
- [NVD entry CVE-2026-21589](https://nvd.nist.gov/vuln/detail/CVE-2026-21589)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21589)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [jira.atlassian.com](https://jira.atlassian.com/browse/BAM-26567)
- [jira.atlassian.com](https://jira.atlassian.com/browse/BSERV-20604)
- [jira.atlassian.com](https://jira.atlassian.com/browse/CONFSERVER-104488)
- [jira.atlassian.com](https://jira.atlassian.com/browse/CRUC-8741)
- [jira.atlassian.com](https://jira.atlassian.com/browse/CWD-6610)
- [jira.atlassian.com](https://jira.atlassian.com/browse/FE-7583)
- [jira.atlassian.com](https://jira.atlassian.com/browse/JRASERVER-79546)
- [jira.atlassian.com](https://jira.atlassian.com/browse/JSDSERVER-16809)
- [github.com](https://github.com/watchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-21589)

---
Source page: https://erroneo.us/security/cve/CVE-2026-21589/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt