Confluence DC DoS vuln (auth) in v9.0.1-10.2.0
CVE-2026-21577 Published on July 21, 2026
This High severity DoS (Denial of Service) vulnerability was introduced in versions 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 9.2.17 Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.7 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.
Weakness Type
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-21577 has been classified to as a Resource Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-21577
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Affected Versions
Atlassian Confluence Data Center:- Version 10.2.0 to 10.2.6 is affected.
- Version 10.1.0 to 10.1.2 is affected.
- Version 10.0.2 to 10.0.3 is affected.
- Version 9.5.1 to 9.5.4 is affected.
- Version 9.4.0 to 9.4.1 is affected.
- Version 9.3.1 to 9.3.2 is affected.
- Version 9.2.0 to 9.2.15 is affected.
- Version 9.1.0 to 9.1.1 is affected.
- Version 9.0.1 to 9.0.3 is affected.
- Version 10.2.7 to 10.2.14 is unaffected.
- Version 9.2.17 to 9.2.22 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.