# CVE-2026-21588: Atlassian Confluence Data Center DoS in authenticated request handling

Source: https://junglewise.ai/threats/cve-2026-21588-atlassian-confluence-data-center-dos-in-authenticated-request  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-21588 · Severity: info · CVSS 7.1 · Published 2026-09-15

Confluence Data Center is a widely deployed enterprise document collaboration platform used by organizations to manage documentation and team knowledge. An authenticated user can exploit a denial-of-service vulnerability to temporarily or permanently disrupt the availability of a Confluence instance, preventing legitimate users from accessing documents and collaboration features. Remediation requires upgrading to patched versions 9.2.24, 10.2.17, or later.

Technologies: [Atlassian Confluence Data Center](https://junglewise.ai/threats/technologies/confluence-data-center). Vendors: [Atlassian](https://junglewise.ai/threats/vendors/atlassian).

## Quick answers

**Is CVE-2026-21588 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-21588 being exploited in the wild.

**How severe is CVE-2026-21588?** Informational severity, with a CVSS score of 7.1, published 15 September 2026.

**Which products and versions are affected?** Atlassian Confluence Data Center 8.9.0 through 10.2.16 (fixed in 9.2.24, 10.2.17 and later).

**Is there a fix for CVE-2026-21588?** A patch was published on 2026-09-15: Fixed versions 9.2.24 and 10.2.17 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-21588 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-21588?** Check whether you run Atlassian Confluence Data Center at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This is a denial-of-service vulnerability affecting Confluence Data Center versions 8.9.0 through 10.2.x. The vulnerability requires prior authentication but allows an attacker to cause resource exhaustion or service disruption via a crafted request. The attack vector is network-based (AV:N) with low complexity (AC:L), and requires user login credentials (PR:L). An authenticated attacker can indefinitely disrupt services of the affected host. The vulnerability has been patched in Confluence Data Center 9.2.24 and 10.2.17 or later. CVSS v4.0 score is 7.1 (High), with the primary impact being availability (VA:H).

## Affected products

- Atlassian Confluence Data Center 8.9.0 through 10.2.16 (fixed in 9.2.24, 10.2.17 and later)

## Timeline

- 2026-09-15: disclosed: Published in Atlassian Security Bulletin
- 2026-09-15: patched: Fixed versions 9.2.24 and 10.2.17 released

## References

- [https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209](https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209)
- [https://jira.atlassian.com/browse/CONFSERVER-104451](https://jira.atlassian.com/browse/CONFSERVER-104451)

## Related threats

- [Atlassian Data Center arbitrary file access without authentication](https://junglewise.ai/threats/cve-2026-21589-h3-summary-this-is-a-vulnerability-in-bitbucket-data-center)
- [Atlassian Confluence Data Center improper authorization](https://junglewise.ai/threats/cve-2026-21586-atlassian-confluence-data-center-improper-authorization)
- [Atlassian Confluence Data Center information disclosure](https://junglewise.ai/threats/cve-2026-21579-atlassian-confluence-data-center-information-disclosure)
- [Atlassian Confluence Data Center denial of service](https://junglewise.ai/threats/cve-2026-21577-atlassian-confluence-data-center-denial-of-service)
- [Atlassian Confluence Data Center and Server Template Injection Vulnerability](https://junglewise.ai/threats/cve-2023-22527-atlassian-confluence-data-center-and-server-template-injection)