CVE-2026-21588
Received Received - Intake

Denial of Service in Confluence Data Center

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: Atlassian

Description
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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
CVE-2026-21588
EUVD
EUVD-2026-78937

Affected Vendors & Products

Showing 12 associated CPEs
Vendor Product Version / Range
atlassian confluence_data_center From 9.2.24 (inc)
atlassian confluence_data_center From 10.2.17 (inc)
atlassian confluence_data_center 8.9
atlassian confluence_data_center 9.0
atlassian confluence_data_center 9.1
atlassian confluence_data_center 9.2
atlassian confluence_data_center 9.3
atlassian confluence_data_center 9.4
atlassian confluence_data_center 9.5
atlassian confluence_data_center 10.0
atlassian confluence_data_center 10.1
atlassian confluence_data_center 10.2

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a High severity Denial of Service (DoS) vulnerability affecting specific versions of Confluence Data Center. It allows an authenticated attacker to disrupt services by making resources unavailable to intended users temporarily or indefinitely.

Impact Analysis

The vulnerability can cause service disruptions, making Confluence Data Center unavailable to users. This may lead to downtime, loss of productivity, and potential data access issues for affected organizations.

Mitigation Strategies
  • Upgrade Confluence Data Center to the latest version or a supported fixed version (e.g., 9.2.24 or 10.2.17).
  • If immediate upgrade is not possible, apply the recommended patches for your current version.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-21588. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart