CVE-2026-21580
Summary
| CVE | CVE-2026-21580 |
|---|---|
| State | PUBLISHED |
| Assigner | atlassian |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-18 22:16:50 UTC |
| Updated | 2026-08-21 15:16:39 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 9.3 CRITICAL from [email protected]
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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
EPSS: 0.003550000 probability, percentile 0.288130000 (date 2026-08-20)
Problem Types: CWE-79 | Stored XSS | CWE-79 CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 9.3 | CRITICAL | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | DECLARED | 8.6 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Atlassian | Confluence Data Center | affected 10.2.0 to 10.2.11 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 10.1.0 to 10.1.2 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 10.0.2 to 10.0.3 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.5.1 to 9.5.4 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.4.0 to 9.4.1 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.3.1 to 9.3.2 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.2.0 to 9.2.20 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.1.0 to 9.1.1 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 9.0.3 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 8.9.6 to 8.9.8 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 8.5.15 to 8.5.31 | Not specified |
| CNA | Atlassian | Confluence Data Center | affected 7.19.27 to 7.19.30 | Not specified |
| CNA | Atlassian | Confluence Data Center | unaffected 10.2.13 to 10.2.15 | Not specified |
| CNA | Atlassian | Confluence Data Center | unaffected 9.2.21 to 9.2.23 | Not specified |
| CNA | Atlassian | Confluence Server | affected 8.5.15 to 8.5.31 | Not specified |
| CNA | Atlassian | Confluence Server | affected 7.19.27 to 7.19.30 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| confluence.atlassian.com/pages/viewpage.action | [email protected] | confluence.atlassian.com | |
| jira.atlassian.com/browse/CONFSERVER-104381 | [email protected] | jira.atlassian.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.