CVE-2025-53641 is a high-severity Server-Side Request Forgery (SSRF) vulnerability identified in the Postiz frontend application, an AI-driven social media scheduling tool developed by gitroomhq. The vulnerability affects versions from 1.45.1 up to, but not including, 1.62.3. The core issue arises from the application's improper handling of HTTP headers, allowing an attacker to inject arbitrary HTTP headers into the middleware pipeline. This injection flaw enables the attacker to coerce the server hosting the Postiz application to initiate unauthorized outbound HTTP requests to arbitrary destinations. SSRF vulnerabilities like this can be leveraged to access internal systems that are otherwise inaccessible externally, potentially leading to information disclosure, internal network reconnaissance, or further exploitation of internal services. The vulnerability does not require authentication or user interaction, making it easier for remote attackers to exploit. The CVSS v3.1 score of 8.2 reflects the high impact on confidentiality due to potential unauthorized data access, with a low attack complexity and no privileges required. The integrity impact is limited, and availability is not affected. Although no known exploits are currently reported in the wild, the vulnerability's nature and ease of exploitation make it a significant risk. The issue was publicly disclosed on July 11, 2025, and fixed in version 1.62.3 of the Postiz application.

For European organizations using the Postiz application versions between 1.45.1 and 1.62.3, this SSRF vulnerability poses a substantial risk. Exploitation could allow attackers to bypass perimeter defenses and access internal network resources, including sensitive databases, internal APIs, or cloud metadata services, potentially leading to data breaches or lateral movement within the network. Given Postiz's role in managing social media scheduling, compromise could also lead to unauthorized manipulation or leakage of scheduled content, damaging brand reputation. Additionally, attackers could use the SSRF to scan internal networks or pivot to other critical infrastructure, increasing the attack surface. The lack of required authentication means that attackers can exploit this vulnerability remotely without valid credentials, increasing the likelihood of attacks. European organizations with strict data protection regulations, such as GDPR, face increased compliance risks if sensitive data is exposed due to this vulnerability. The potential for internal reconnaissance and data exfiltration makes this a critical concern for enterprises, government agencies, and media companies relying on Postiz for social media management.

European organizations should immediately verify their Postiz application version and upgrade to version 1.62.3 or later, where the vulnerability is patched. If immediate upgrading is not feasible, implement strict network egress filtering on servers hosting Postiz to restrict outbound HTTP requests only to trusted destinations, thereby limiting SSRF exploitation scope. Employ Web Application Firewalls (WAFs) with custom rules to detect and block unusual HTTP header injections or suspicious outbound request patterns. Conduct thorough internal network segmentation to minimize the impact of potential SSRF exploitation, ensuring that critical internal services are not directly accessible from the Postiz server. Monitor application logs and network traffic for anomalous outbound requests originating from the Postiz server. Additionally, perform regular security assessments and penetration testing focusing on SSRF vectors to detect similar vulnerabilities. Educate development teams on secure coding practices to prevent header injection flaws in future releases. Finally, maintain an incident response plan tailored to SSRF incidents to enable rapid containment and remediation if exploitation is detected.