CVE-2026-21580
CriticalCVSS 9.3Summary
A Critical Stored XSS, Privilege Escalation, and Security Misconfiguration vulnerability in Confluence Data Center and Server allows an unauthenticated attacker to execute arbitrary HTML or JavaScript in a victim's browser, perform actions as a higher-privileged user, and exploit security best-practice oversights.
Risk Assessment
An attacker could compromise user accounts, escalate privileges, and gain unauthorized access to the system, potentially leading to data breaches and integrity loss.
Recommendation
Upgrade Confluence Data Center and Server to version 9.2.21 or later (for 9.2) and 10.2.13 or later (for 10.2). If possible, apply the latest available version.
Original NVD description (English source)
This Critical severity Stored XSS, PrivEsc (Privilege Escalation), and Security Misconfiguration vulnerability was introduced in versions 7.1.1, 7.4.0, 7.13.0, 7.17.0, 7.19.0, 8.0.0, 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 of Confluence Data Center and Server. This Stored XSS, PrivEsc (Privilege Escalation), and Security Misconfiguration vulnerability, with a CVSS Score of 8.6, allows an unauthenticated attacker to execute arbitrary HTML or JavaScript code on a victims browser, perform actions as a higher-privileged user, and to get into the system utilizing loopholes exposed from security best-practices being overlooked. Atlassian recommends that Confluence Data Center and Server 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 and Server 9.2: Upgrade to a release greater than or equal to 9.2.21 Confluence Data Center and Server 10.2: Upgrade to a release greater than or equal to 10.2.13 See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center and Server from the download center ([https://www.atlassian.com/software/confluence/download-archives]). This vulnerability was reported via our Bug Bounty program.