CVE-2026-21588
HighCVSS 7.1Summary
A High severity Denial of Service (DoS) vulnerability in Confluence Data Center 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. An authenticated attacker can cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network.
Risk Assessment
An authenticated attacker can cause Confluence service unavailability, disrupting organizational work. This may lead to interruptions in access to documentation and collaboration.
Recommendation
Upgrade Confluence Data Center to the latest version or at least to 9.2.24 (for the 9.2 branch) or 10.2.17 (for the 10.2 branch).
Other vulnerabilities in Confluence Data Center
See all- CVE-2026-21586High
A High severity Improper Authorization vulnerability in Confluence Data Center versions 7.4.0, 7.13.0, 8.5.0, 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. An authenticated attacker can gain unintended access, potentially leading to exposure of resources or functionality, and possibly enabling sensitive information disclosure or arbitrary code execution.
- CVE-2026-21579High
Information disclosure vulnerability in Confluence Data Center. An unauthenticated attacker can access sensitive information without authentication.
- CVE-2026-21577Medium
High severity DoS vulnerability in Confluence Data Center versions 9.0.1 through 10.2.0. An authenticated attacker can cause temporary or permanent unavailability of resources by disrupting services of a network host.
Original NVD description (English source)
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.