CVE-2024-55082 is a high-severity Server-Side Request Forgery (SSRF) vulnerability identified in Stirling-PDF version 0.35.1, affecting the /url-to-pdf endpoint. SSRF vulnerabilities occur when an attacker can manipulate a server to send HTTP requests to arbitrary domains, including internal network resources that are otherwise inaccessible externally. In this case, the endpoint accepts a URL parameter intended to fetch a PDF resource, but lacks proper validation or sanitization, enabling attackers to craft requests that cause the server to retrieve data from internal services or sensitive external endpoints. This can lead to unauthorized access to sensitive information such as internal metadata, configuration files, or other protected resources. The vulnerability does not require any authentication or user interaction, making it easier to exploit remotely over the network. The CVSS v3.1 base score is 7.5, reflecting high confidentiality impact, no impact on integrity or availability, and low attack complexity. No patches or fixes have been released yet, and no active exploitation has been reported. The vulnerability is categorized under CWE-918 (Server-Side Request Forgery). Given the nature of SSRF, attackers could leverage this flaw for reconnaissance or to pivot attacks within a network, potentially leading to further compromise if combined with other vulnerabilities.

The primary impact of CVE-2024-55082 is the unauthorized disclosure of sensitive information within an organization's internal network or from protected external resources. Attackers exploiting this SSRF vulnerability can bypass network segmentation and firewall rules, accessing internal services that are not exposed to the internet. This can lead to leakage of confidential data, such as internal APIs, metadata services, or administrative interfaces. While the vulnerability does not directly affect data integrity or system availability, the information gained can facilitate subsequent attacks, including privilege escalation or lateral movement. Organizations relying on Stirling-PDF for PDF generation in web applications or automated workflows are at risk, especially if the vulnerable endpoint is exposed to untrusted users or the internet. The absence of authentication requirements and user interaction increases the likelihood of exploitation. The lack of patches means organizations must rely on mitigations until an official fix is available. Overall, this vulnerability poses a significant risk to confidentiality and could be a stepping stone for more severe attacks.

1. Immediately restrict access to the /url-to-pdf endpoint by implementing network-level controls such as IP whitelisting or VPN requirements to limit exposure to trusted users only. 2. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious SSRF patterns, such as requests containing internal IP ranges or localhost references. 3. Implement strict input validation and sanitization on the URL parameter to ensure only allowed domains or protocols are accepted, using allowlists rather than blocklists. 4. Monitor server logs for unusual outbound HTTP requests initiated by the /url-to-pdf endpoint, focusing on internal IP addresses or unexpected destinations. 5. If possible, isolate the PDF generation service in a segmented network zone with minimal access to sensitive internal resources. 6. Stay updated with Stirling-PDF vendor announcements and apply patches promptly once available. 7. Conduct internal security assessments to identify any sensitive services that could be targeted via SSRF and harden them accordingly. 8. Consider implementing outbound request proxying with strict controls to prevent arbitrary external or internal requests. These measures collectively reduce the attack surface and limit the potential impact until a permanent fix is released.