Vulnerability · Published Sep 15, 2026 · Assigned by atlassian
CVE-2026-21588
High 7.1
In plain English
A high-severity uncontrolled resource consumption in Confluence Data Center from Atlassian. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Atlassian | Confluence Data Center | 10.2.0 to 10.2.1510.1.0 to 10.1.210.0.2 to 10.0.39.5.1 to 9.5.49.4.0 to 9.4.19.3.1 to 9.3.29.2.0 to 9.2.239.1.0 to 9.1.1 |
Weakness: CWE-400 · Vector: 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