CVE-2021-28627 is a Server-Side Request Forgery (SSRF) vulnerability identified in Adobe Experience Manager (AEM), specifically affecting the Adobe Experience Manager Cloud Service and versions 6.5.8.0 and below. SSRF vulnerabilities allow an attacker to induce the server-side application to make HTTP requests to arbitrary domains or internal systems that are otherwise inaccessible. In this case, an authenticated attacker can exploit the vulnerability to bypass dispatcher-level restrictions and contact internal or blocked systems. The vulnerability does not require user interaction beyond authentication, meaning that once an attacker has valid credentials, they can leverage this flaw without additional user involvement. This SSRF could be used to access internal services, potentially leading to information disclosure, lateral movement within the network, or further exploitation of internal systems. The vulnerability is categorized under CWE-918, which relates to improper restriction of outgoing requests by a server. Although no known exploits have been reported in the wild, the risk remains significant due to the potential for internal network reconnaissance and pivoting. The lack of a publicly available patch link suggests that mitigation may require applying updates from Adobe or implementing compensating controls. The vulnerability was reserved in March 2021 and published in August 2021, indicating it has been known for some time but with medium severity assigned by Adobe.

For European organizations using Adobe Experience Manager, particularly those leveraging the Cloud Service or running versions 6.5.8.0 and below, this vulnerability poses a risk of unauthorized internal network access. Exploitation could allow attackers to bypass perimeter defenses enforced by the dispatcher, potentially accessing sensitive internal services, databases, or administrative interfaces not intended to be exposed externally. This could lead to confidentiality breaches if sensitive data is accessed or integrity compromises if internal services are manipulated. Availability impacts are possible if attackers use SSRF to trigger resource exhaustion or denial-of-service conditions on internal systems. Given that AEM is widely used in sectors such as government, finance, healthcare, and media across Europe, the vulnerability could facilitate targeted attacks against critical infrastructure or sensitive data repositories. The requirement for authentication limits the attack surface but does not eliminate risk, especially in environments where credential compromise or insider threats are possible. The absence of known exploits in the wild reduces immediate risk but does not preclude future exploitation, especially as attackers develop new techniques. Overall, the vulnerability could undermine trust in digital services and disrupt business operations if exploited.

European organizations should prioritize the following specific mitigation steps: 1) Immediately verify the version of Adobe Experience Manager in use and plan for an upgrade to a patched version once Adobe releases it. 2) Restrict and monitor access to AEM administrative interfaces to trusted personnel only, enforcing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. 3) Implement strict egress filtering and network segmentation to limit the ability of AEM servers to make arbitrary outbound requests, thereby reducing the impact of SSRF exploitation. 4) Use web application firewalls (WAFs) with custom rules to detect and block suspicious SSRF patterns targeting internal endpoints. 5) Conduct regular audits of logs for unusual outbound requests originating from AEM servers, focusing on requests to internal IP ranges or unexpected domains. 6) Educate administrators and developers about SSRF risks and ensure secure coding practices to prevent similar vulnerabilities in custom AEM components. 7) If immediate patching is not possible, consider disabling or restricting features that allow server-side request initiation within AEM until a fix is applied. 8) Engage with Adobe support to obtain any available interim patches or recommended configurations. These steps go beyond generic advice by focusing on network-level controls, access management, and monitoring tailored to the nature of this SSRF vulnerability.