CVE-2021-28626 is an Improper Authorization vulnerability (CWE-285) found in Adobe Experience Manager (AEM), specifically affecting the Adobe Experience Manager Cloud Service and versions 6.5.8.0 and below. The vulnerability allows an unauthenticated attacker to create nodes under a specific location within the AEM repository. This unauthorized node creation can be exploited to cause an application denial-of-service (DoS), potentially disrupting the availability of the service. The vulnerability arises due to insufficient authorization checks on node creation operations, permitting attackers to bypass access controls. Notably, exploitation does not require any user interaction, making automated or remote exploitation feasible. Although no known exploits have been reported in the wild, the vulnerability poses a significant risk due to the critical role AEM plays in managing digital content and web experiences for enterprises. The lack of a patch link suggests that remediation may require applying updates from Adobe or implementing compensating controls. The vulnerability impacts confidentiality minimally, but integrity and availability are at risk because unauthorized node creation can corrupt or overload the system, leading to service disruption.

For European organizations, the impact of CVE-2021-28626 could be substantial, especially for those relying on Adobe Experience Manager for content management and digital experience delivery. A successful exploitation could lead to denial-of-service conditions, causing downtime of public-facing websites or internal portals, which can affect customer engagement, brand reputation, and operational continuity. Industries such as finance, government, media, and retail, which often use AEM for critical digital services, may experience service outages or degraded performance. Additionally, the unauthorized creation of nodes could be leveraged as a foothold for further attacks or data manipulation if combined with other vulnerabilities. The lack of authentication requirement lowers the barrier for attackers, increasing the risk of automated attacks targeting exposed AEM instances. Given the centrality of AEM in digital infrastructure, this vulnerability could disrupt business operations and lead to financial losses and regulatory scrutiny under European data protection laws if service disruptions affect data availability or integrity.

To mitigate CVE-2021-28626, European organizations should take the following specific actions: 1) Immediately verify the version of Adobe Experience Manager in use and prioritize upgrading to the latest patched version provided by Adobe once available. 2) Restrict external access to AEM author and publish instances by implementing network segmentation and firewall rules to limit exposure to trusted IP ranges only. 3) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious node creation requests or anomalous API calls targeting repository nodes. 4) Monitor AEM logs for unusual node creation activities or unauthorized access attempts to enable early detection of exploitation attempts. 5) Implement strict access control policies within AEM, ensuring that only authorized users and services have permissions to create or modify repository nodes. 6) Consider deploying rate limiting on AEM endpoints to reduce the risk of DoS attacks stemming from automated exploitation. 7) Engage with Adobe support channels to obtain official patches or workarounds and stay informed about updates related to this vulnerability. 8) Conduct regular security assessments and penetration testing focused on AEM deployments to identify and remediate authorization weaknesses proactively.