CVE-2026-21579 Overview
CVE-2026-21579 is a High severity information disclosure vulnerability in Atlassian Confluence Data Center. The flaw allows an unauthenticated remote attacker to view sensitive information exposed by the application. Atlassian introduced the vulnerability in Confluence Data Center versions 7.17.0, 7.19.0, 8.5.0, 8.9.0, 9.0.1, 9.1.0, 9.2.0, 10.0.2, 10.1.0, and 10.2.0. The issue was reported through the Atlassian internal security program and is tracked under CONFSERVER-104340. It maps to the weakness class [CWE-200] (Exposure of Sensitive Information to an Unauthorized Actor).
Critical Impact
Unauthenticated attackers can access sensitive information over the network without user interaction, exposing high-value data hosted in Confluence Data Center deployments.
Affected Products
- Atlassian Confluence Data Center versions 7.17.0, 7.19.0, 8.5.0, 8.9.0
- Atlassian Confluence Data Center versions 9.0.1, 9.1.0, 9.2.0 (prior to 9.2.22)
- Atlassian Confluence Data Center versions 10.0.2, 10.1.0, 10.2.0 (prior to 10.2.14)
Discovery Timeline
- 2026-07-21 - CVE-2026-21579 published to NVD
- 2026-07-22 - Last updated in NVD database
Technical Details for CVE-2026-21579
Vulnerability Analysis
CVE-2026-21579 is an information disclosure weakness [CWE-200] in Confluence Data Center. An unauthenticated attacker can reach the vulnerable endpoint over the network and retrieve sensitive data without prior credentials or user interaction. Atlassian classifies the impact as confidentiality-only, with no direct effect on integrity or availability. Exposed data in a Confluence deployment may include internal application details, configuration artifacts, or content metadata that supports further attacks. The vulnerability affects long-lived Confluence Data Center release lines going back to 7.17.x, indicating a defect present across multiple maintenance branches.
Root Cause
The underlying cause is improper protection of a sensitive resource within Confluence Data Center, consistent with [CWE-200]. Atlassian's advisory does not publicly detail the specific endpoint or component, but the fix ships in Confluence Data Center 9.2.22 and 10.2.14 and the latest branch releases. See the Atlassian advisory for vendor-provided details.
Attack Vector
The attack vector is network-based. An attacker sends crafted requests to an exposed Confluence Data Center instance and receives sensitive information in the response. No authentication or user interaction is required. Attack complexity is elevated by an attack requirement condition, meaning specific preconditions in the target deployment must exist for successful exploitation. There is no public proof-of-concept exploit at this time, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is 0.274%.
No verified exploit code is available. Refer to CONFSERVER-104340 for tracking and technical context published by the vendor.
Detection Methods for CVE-2026-21579
Indicators of Compromise
- Unauthenticated HTTP requests to Confluence Data Center endpoints returning non-empty response bodies containing configuration, user, or content metadata.
- Anomalous spikes in requests from a single external source to Confluence application paths without accompanying login events.
- Access log entries returning HTTP 200 for resources that normally require authenticated sessions.
Detection Strategies
- Inventory all Confluence Data Center instances and compare installed versions against the fixed releases 9.2.22 and 10.2.14.
- Enable and centralize Confluence access and audit logs, then hunt for repeated unauthenticated requests to sensitive endpoints.
- Correlate web application firewall (WAF) telemetry with Confluence logs to identify probing patterns targeting the affected endpoint once vendor detail is published.
Monitoring Recommendations
- Alert on unauthenticated requests to Confluence paths that historically require a session cookie or CSRF token.
- Monitor egress traffic from Confluence servers to identify data staging that may follow disclosure of sensitive metadata.
- Track version banners and API responses to detect Confluence instances still running vulnerable releases after patch windows.
How to Mitigate CVE-2026-21579
Immediate Actions Required
- Upgrade Confluence Data Center 9.2.x to 9.2.22 or later, and 10.2.x to 10.2.14 or later.
- For all other affected branches, upgrade to the latest supported Confluence Data Center release listed in the Confluence release notes.
- Restrict network exposure of Confluence Data Center to trusted networks or VPN clients until patching completes.
- Review Confluence access logs for unauthenticated requests dating back to when the affected versions were deployed.
Patch Information
Atlassian has released fixed versions of Confluence Data Center. Customers on the 9.2 branch should install 9.2.22 or later. Customers on the 10.2 branch should install 10.2.14 or later. Customers on 7.17, 7.19, 8.5, 8.9, 9.0, 9.1, 10.0, or 10.1 should move to a supported branch containing the fix. Download packages are available from the Atlassian download archives.
Workarounds
- Place Confluence Data Center behind an authenticating reverse proxy or SSO gateway to block anonymous requests.
- Apply WAF rules to deny unauthenticated access to non-public Confluence endpoints until upgrades are completed.
- Remove internet exposure of Confluence Data Center instances that do not require public reachability.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
