CVE-2026-21582 in Crowd Data Center
Summary
by MITRE • 08/19/2026
This High severity BASM (Broken Authentication & Session Management) vulnerability known as CVE-2026-21582 was introduced in version 7.2.1 of Crowd Data Center.
This BASM (Broken Authentication & Session Management) vulnerability, with a CVSS Score of 8.8, allows an unauthenticated attacker to perform actions as another user. Atlassian recommends that Crowd 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: Crowd Data Center 7.2: Upgrade to a release greater than or equal to 7.2.2 See the release notes (https://confluence.atlassian.com/crowd/crowd-release-notes-199094.html). You can download the latest version of Crowd Data Center from the download center (https://www.atlassian.com/software/crowd/download-archive). This vulnerability was reported via our Penetration Testing program.
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Analysis
by VulDB Data Team • 08/20/2026
The security advisory for CVE-2026-21582 identifies a critical Broken Authentication and Session Management flaw within Atlassian Crowd Data Center, specifically affecting version 7.2.1 and potentially earlier versions in the 7.2 series that have not received the necessary patches. This vulnerability carries a high severity rating with a CVSS score of 8.8, indicating a significant risk to system integrity and confidentiality. The core issue lies in the application's handling of user sessions and authentication tokens, which allows an unauthenticated attacker to bypass security controls and impersonate legitimate users. By exploiting this flaw, an adversary can perform actions under the context of another user without possessing valid credentials for that account, effectively breaking the fundamental trust model of the identity management system.
From a technical perspective, this vulnerability aligns with CWE-287 Improper Authentication and CWE-384 Session Fixation or Weak Session Management practices often found in web applications where session identifiers are not properly invalidated upon privilege changes or logout, or where tokens can be predicted or reused by unauthorized parties. The exploitation of CVE-2026-21582 enables an attacker to hijack active sessions or forge authentication states, leading to a complete compromise of user identity within the Crowd Data Center environment. This capability is particularly dangerous in enterprise settings because it allows lateral movement and privilege escalation without triggering traditional credential-based intrusion detection systems that rely on failed login attempts as primary indicators of compromise.
The operational impact of this vulnerability extends beyond simple account takeover. Since Crowd serves as a central directory for many organizations, managing authentication for numerous downstream applications such as Jira, Confluence, Bitbucket, and other Atlassian products or third-party integrations, compromising the identity layer affects the entire ecosystem. An attacker who successfully exploits this flaw can access sensitive corporate data, modify user permissions, create backdoor accounts, or disrupt service availability by manipulating administrative settings. The ability to act as another user means that audit logs may reflect legitimate activity rather than malicious intent, complicating forensic analysis and incident response efforts significantly.
This vulnerability was discovered through Atlassian's Penetration Testing program, highlighting the importance of continuous security assessment in maintaining robust defense postures against sophisticated threats. To mitigate this risk, organizations running Crowd Data Center version 7.2.1 must immediately upgrade to a patched release. Specifically, customers should migrate to any version greater than or equal to 7.2.2 within the 7.2 branch. For those unable to perform an immediate in-place upgrade due to compatibility constraints with other integrated Atlassian tools, it is imperative to identify and deploy one of the specified supported fixed versions that maintain stability while addressing the security gap.
Administrators should verify their current Crowd Data Center version via the administration dashboard and initiate the upgrade process as soon as possible after validating backup integrity. It is also recommended to review access logs for any anomalous activity prior to patching, although such evidence may be scarce due to the nature of session hijacking attacks that mimic legitimate user behavior. Post-upgrade, organizations should enforce strict password policies, implement multi-factor authentication where supported by integrated applications, and regularly rotate service account credentials to minimize the window of exposure if similar vulnerabilities are discovered in future releases. Monitoring for unusual login patterns or token usage can provide additional layers of defense against exploitation attempts that might persist during transition periods.