CVE-2021-28625 is a Cross-Site Scripting (XSS) vulnerability identified in Adobe Experience Manager (AEM), specifically affecting the Cloud Service offering and versions 6.5.8.0 and below. This vulnerability arises from insufficient input validation or sanitization in form fields within AEM, allowing an attacker to inject malicious JavaScript code. When a victim accesses a page containing the vulnerable form field, the injected script executes in their browser context. This can lead to session hijacking, credential theft, unauthorized actions performed on behalf of the user, or redirection to malicious sites. The vulnerability is classified under CWE-79, which pertains to improper neutralization of input during web page generation. Although no known exploits have been reported in the wild, the nature of XSS vulnerabilities makes them a common vector for attacks, especially in web applications with significant user interaction. Adobe Experience Manager is a widely used enterprise content management system, often deployed by large organizations to manage web content and digital assets, making this vulnerability a concern for entities relying on AEM for their web presence and digital marketing. The vulnerability does not require authentication or user interaction beyond visiting a compromised or maliciously crafted page, increasing its potential reach. The lack of a patch link suggests that remediation may require applying updates from Adobe or implementing custom input validation controls until an official fix is available.

For European organizations, the impact of this XSS vulnerability in Adobe Experience Manager can be significant. Many enterprises, including government agencies, financial institutions, and large corporations across Europe, use AEM to manage public-facing websites and internal portals. Exploitation could lead to theft of sensitive user credentials, unauthorized access to internal systems, defacement of websites, or distribution of malware to visitors. This could damage organizational reputation, lead to regulatory non-compliance under GDPR due to data breaches, and cause operational disruptions. The vulnerability could also be leveraged in targeted phishing campaigns or to escalate attacks within the victim's network. Given the widespread use of AEM in sectors critical to European infrastructure and commerce, the potential for data leakage and service disruption is a notable risk. Additionally, the ability to execute scripts in users' browsers could undermine trust in affected organizations' digital services.

1. Immediate mitigation should include implementing strict input validation and output encoding on all form fields within Adobe Experience Manager to prevent injection of malicious scripts. 2. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 3. Monitor web traffic and logs for unusual activity or attempts to exploit form fields, using web application firewalls (WAFs) with updated rules targeting XSS patterns specific to AEM. 4. Apply the latest Adobe Experience Manager patches and updates as soon as they become available, ensuring that the affected versions are upgraded beyond 6.5.8.0. 5. Conduct security awareness training for developers and administrators managing AEM instances to recognize and remediate XSS vulnerabilities. 6. For organizations unable to immediately patch, consider temporarily disabling or restricting access to vulnerable forms or pages, especially those accessible to unauthenticated users. 7. Regularly audit and test AEM deployments using automated scanning tools and manual penetration testing focused on XSS vectors to identify and remediate vulnerabilities proactively.