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Severe, 6 weeks1496Projects326

1496 severe, 6 weeks · 326 projects

AtlassianCVE-2026-21588

Atlassian Confluence Data Center: denial of service

Atlassian

CVE-2026-21588 · Published Sep 15, 2026 · updated Sep 16, 2026

High7.1
No fix yet
Atlassian advisory

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 versions

PackageAffectedFixed in
Confluence Data Center
Product
<= 10.2.0 to 10.2.15No fix yet
<= 10.1.0 to 10.1.2No fix yet
<= 10.0.2 to 10.0.3No fix yet
<= 9.5.1 to 9.5.4No fix yet
Details and references
CVSS 4.0
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity from
the vendor (its own CVE record or advisory)
Weakness
CWE-400

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