CVE-2021-21009 is a Server-Side Request Forgery (SSRF) vulnerability identified in multiple versions of Adobe Campaign Classic Gold Standard, specifically versions 10 and earlier, 20.3.1 and earlier, 20.2.3 and earlier, 20.1.3 and earlier, 19.2.3 and earlier, and 19.1.7 and earlier. Adobe Campaign is a marketing automation software widely used for managing customer campaigns and communications. SSRF vulnerabilities occur when an attacker can manipulate a server to send unauthorized requests to internal or external resources, potentially bypassing network access controls. In this case, an attacker exploiting this vulnerability could coerce the Adobe Campaign server to issue arbitrary HTTP requests, which may target internal systems not directly accessible from the outside or external systems that the server can reach. This could lead to unauthorized information disclosure, internal network reconnaissance, or interaction with otherwise protected services. The vulnerability does not require authentication or user interaction, increasing the risk of exploitation. Although no known exploits are reported in the wild, the potential for misuse exists given the nature of SSRF attacks. The vulnerability is classified under CWE-918, indicating weaknesses in server-side request handling. The lack of a CVSS score necessitates an assessment based on impact and exploitability factors. Given Adobe Campaign's role in handling sensitive marketing and customer data, unauthorized requests could compromise confidentiality and integrity of data or disrupt availability by targeting internal services. The vulnerability was publicly disclosed on January 13, 2021, and Adobe has not provided direct patch links in the provided information, suggesting the need for organizations to verify and apply vendor updates promptly.

For European organizations, the exploitation of this SSRF vulnerability in Adobe Campaign could have significant consequences. Adobe Campaign is commonly used by enterprises and public sector organizations to manage customer engagement and communications, often containing sensitive personal data protected under GDPR. An attacker leveraging this vulnerability could access internal systems behind firewalls, potentially extracting confidential customer information or internal business data, leading to data breaches and regulatory penalties. Additionally, the ability to send unauthorized requests could enable lateral movement within corporate networks or interaction with cloud services, amplifying the scope of compromise. Disruption of marketing operations could also impact business continuity and reputation. Given the medium severity classification and the absence of required authentication, the threat is more accessible to attackers, increasing risk. The impact on confidentiality is high due to potential data exposure, integrity could be compromised if unauthorized requests modify internal resources, and availability could be affected if internal services are targeted for denial-of-service conditions. The overall risk is heightened for organizations with complex internal networks and those relying heavily on Adobe Campaign for critical communications.

European organizations should undertake a multi-layered approach to mitigate this SSRF vulnerability. First, verify the Adobe Campaign version in use and promptly apply any available security updates or patches from Adobe, even if not explicitly linked in the provided data, by consulting Adobe's official security advisories. If immediate patching is not possible, implement network-level controls such as restricting outbound HTTP/HTTPS requests from the Adobe Campaign server to only trusted endpoints using firewall rules or proxy configurations. Employ strict input validation and sanitization on any parameters that could influence server-side requests within the application configuration or custom workflows. Monitor logs for unusual outbound requests originating from the Adobe Campaign server to detect potential exploitation attempts. Segment the network to isolate the Adobe Campaign server from sensitive internal systems to limit lateral movement. Additionally, conduct regular security assessments and penetration testing focused on SSRF vectors. Finally, ensure that incident response plans include scenarios involving SSRF exploitation to enable rapid containment and remediation.