CVE-2026-21580

CRITICAL CVSS 4.0: 9.3 EPSS 0.40%
Updated Aug 26, 2026
Atlassian
Parameter Value
CVSS 9.3 (CRITICAL)
Affected Versions 7.19.27 — 9.4.1
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor Atlassian
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 53

Configuration From (including) Up to (excluding)
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
9.4.0 <= 9.4.1
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.4.1:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
9.3.1 <= 9.3.2
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
9.2.0 <= 9.2.20
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.2:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.3:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.4:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.5:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.6:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.7:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.8:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.9:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.10:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.11:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.12:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.13:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.14:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.15:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.16:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.17:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.18:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.19:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.20:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
9.1.0 <= 9.1.1
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.0.3:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
8.9.6 <= 8.9.8
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
8.5.15 <= 8.5.31
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.22:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.23:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.24:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.25:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.26:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.27:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.28:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.29:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.30:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:8.5.31:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*
7.19.27 <= 7.19.30
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.21:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.22:*:*:*:*:*:*:*
Atlassian Confluence_Data_Center
cpe:2.3:a:atlassian:confluence_data_center:9.2.23:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:*
8.5.15 <= 8.5.31
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.22:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.23:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.24:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.25:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.26:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.27:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.28:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.29:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.30:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:8.5.31:*:*:*:*:*:*:*
Atlassian Confluence_Server
cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:*
7.19.27 <= 7.19.30