CVE-2026-21579 in Confluence Data Center
Summary
by MITRE • 07/21/2026
This High severity Information Disclosure vulnerability was introduced in 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 of Confluence Data Center.
This Information Disclosure vulnerability, with a CVSS Score of 8.2, allows an unauthenticated attacker to view sensitive information via an Information Disclosure vulnerability.
Atlassian recommends that Confluence Data Center 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 9.2: Upgrade to a release greater than or equal to 9.2.22
Confluence Data Center 10.2: Upgrade to a release greater than or equal to 10.2.14
See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]).
This vulnerability was reported via our Atlassian (Internal) program.
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Analysis
by VulDB Data Team • 07/21/2026
This information disclosure vulnerability in Atlassian Confluence Data Center represents a critical security flaw that has affected multiple major versions including 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 vulnerability carries a CVSS score of 8.2, indicating high severity risk to organizations that rely on Confluence Data Center for their collaborative workspaces. This flaw allows unauthenticated attackers to access sensitive information without requiring any credentials or prior authorization, making it particularly dangerous in enterprise environments where Confluence serves as a central repository for organizational knowledge and documentation.
The technical nature of this vulnerability stems from inadequate access controls within the Confluence Data Center application, specifically within its information disclosure mechanisms. According to CWE standards, this would be categorized under CWE-200 - Information Exposure, which occurs when an application provides more information than intended, potentially revealing system internals, configuration details, or other sensitive data to unauthorized parties. The vulnerability's presence across multiple version lines suggests a fundamental flaw in the application's security architecture rather than a localized issue that could be addressed through simple patches.
The operational impact of this vulnerability extends beyond simple data exposure, as it can provide attackers with valuable intelligence for subsequent attacks. An unauthenticated attacker who successfully exploits this vulnerability could gain access to confidential documents, internal communication records, system configurations, and potentially user credentials stored within the Confluence environment. This information disclosure could enable more sophisticated attack vectors including privilege escalation, lateral movement within networks, or targeted social engineering campaigns. The fact that this vulnerability affects such a wide range of versions indicates that organizations using Confluence Data Center across different deployment scenarios may be at risk, from small teams to large enterprise installations.
Organizations affected by this vulnerability should prioritize immediate remediation through the recommended upgrade paths provided by Atlassian. The company has specified targeted fixed versions for each affected major release line, with version 9.2.22 and 10.2.14 being the minimum required for protection. This recommendation aligns with industry best practices for vulnerability management as outlined in the MITRE ATT&CK framework, where information gathering techniques represent one of the initial phases that attackers use to plan more extensive operations. Organizations unable to perform immediate upgrades should consider implementing network-level mitigations such as firewall rules restricting access to Confluence services and monitoring for suspicious access patterns.
The vulnerability's discovery through Atlassian's internal reporting program demonstrates responsible disclosure practices, which are crucial for maintaining security hygiene in software ecosystems. This approach allows vendors to develop and release patches before public exploitation occurs, though the widespread impact across multiple versions suggests that organizations may need to perform extensive patching across their deployment environments. The recommended upgrade process should include thorough testing of existing Confluence integrations and customizations to ensure compatibility with the fixed versions. Additionally, security teams should conduct comprehensive audits of their Confluence Data Center instances to identify any additional vulnerabilities that may have been overlooked during routine security assessments, particularly focusing on access control configurations and user permission settings that could compound the risks associated with this information disclosure vulnerability.