Critical severity · published Aug 18, 2026
CVE-2026-21580
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,…
9.3
CVSS
0.5%
EPSS
No
On KEV
Description
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.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
Confluence · Atlassian
10.2.0 to 10.2.11; 10.1.0 to 10.1.2; 10.0.2 to 10.0.3; 9.5.1 to 9.5.4; 9.4.0 to 9.4.1; 9.3.1 to 9.3.2; +6 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21580
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21580
confluence.atlassian.com
https://confluence.atlassian.com/pages/viewpage.action?pageId=1821999768
jira.atlassian.com
https://jira.atlassian.com/browse/CONFSERVER-104381
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