---
id: CVE-2026-21588
title: "This High severity DoS (Denial of Service) vulnerability was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center.\r\n\r\nThis DoS (Denial of Service) vulnerability, wit…"
summary: "This High severity DoS (Denial of Service) vulnerability was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center.\r\n\r\nThis DoS (Denial of Service) vulnerability, wit…"
severity: high
cvss: 7.1
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-400
vendor: Atlassian
product: Confluence Data Center
affected:
  - confluence_data_center 10.2.0 to 10.2.15
  - confluence_data_center 10.1.0 to 10.1.2
  - confluence_data_center 10.0.2 to 10.0.3
  - confluence_data_center 9.5.1 to 9.5.4
  - confluence_data_center 9.4.0 to 9.4.1
  - confluence_data_center 9.3.1 to 9.3.2
  - confluence_data_center 9.2.0 to 9.2.23
  - confluence_data_center 9.1.0 to 9.1.1
  - confluence_data_center 8.9.7 to 8.9.8
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:10:48.873'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-21588'
references:
  - url: 'https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209'
    label: security@atlassian.com
  - url: 'https://jira.atlassian.com/browse/CONFSERVER-104451'
    label: security@atlassian.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-15T17:15:17.585833Z'
cvssSource: cna
ingestedAt: '2026-09-15T17:41:02.861Z'
epss: 0.00289
epssPercentile: 0.21697
---

## Overview

This High severity DoS (Denial of Service) vulnerability was introduced in versions 8.9.0, 9.0.1, 9.1.0, 9.2.0, 9.3.1, 9.4.0, 9.5.1, 10.0.2, 10.1.0, and 10.2.0 of Confluence Data Center.

This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network.

Atlassian recommends that Confluence Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions:
 Confluence Data Center 9.2: Upgrade to a release greater than or equal to 9.2.24

 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.17

See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]).

This vulnerability was reported via our Penetration Testing program.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.