CVE-2025-51591 identifies a Server-Side Request Forgery (SSRF) vulnerability in JGM Pandoc version 3.6.4, a widely used document converter tool. SSRF vulnerabilities occur when an attacker can manipulate server-side requests to access internal or external resources that should be restricted. In this case, the vulnerability arises from the ability to inject a crafted iframe, which can cause the server to make unintended requests. This can lead to unauthorized access to internal infrastructure components, potentially exposing sensitive data or enabling further compromise. The CVSS score of 3.7 reflects a low severity primarily due to the requirement of network access (AV:N), high attack complexity (AC:H), and no privileges or user interaction needed. The impact is limited to confidentiality with no direct integrity or availability effects. No patches are currently linked, and no known exploits have been reported in the wild, indicating this is a newly disclosed vulnerability. The underlying weakness is classified under CWE-918 (SSRF), which typically involves insufficient validation of URLs or request destinations. Organizations using JGM Pandoc 3.6.4 should be aware of this vulnerability and prepare to apply patches once available. Monitoring network traffic for unusual requests and restricting outbound server requests can help mitigate exploitation risk.

For European organizations, the primary impact of CVE-2025-51591 lies in potential unauthorized access to internal network resources via SSRF, which could lead to data exposure or lateral movement within the infrastructure. Although the CVSS score is low, the ability to compromise the entire infrastructure through SSRF indicates a potentially serious risk if chained with other vulnerabilities. Organizations in sectors relying heavily on document processing and conversion, such as publishing, academia, and software development, may be more exposed. The low severity score suggests limited immediate risk, but the lack of patches and the potential for infrastructure compromise necessitate proactive measures. Confidentiality is the main concern, with no direct impact on system integrity or availability. The absence of known exploits reduces immediate threat but does not eliminate future risk. European entities with complex internal networks and less restrictive outbound traffic policies are more vulnerable to SSRF exploitation.

1. Restrict outbound HTTP/HTTPS requests from servers running JGM Pandoc 3.6.4 to only trusted destinations using firewall rules or network segmentation. 2. Implement strict input validation and sanitization on any user-supplied URLs or iframe content processed by Pandoc to prevent injection of malicious requests. 3. Monitor server logs and network traffic for unusual or unexpected outbound requests that could indicate SSRF attempts. 4. Apply security best practices such as running Pandoc with least privilege and isolating it in a sandboxed environment to limit potential impact. 5. Stay alert for official patches or updates from the JGM Pandoc maintainers and apply them promptly once released. 6. Consider deploying Web Application Firewalls (WAFs) capable of detecting and blocking SSRF patterns. 7. Conduct internal security assessments and penetration tests focusing on SSRF vectors in document processing workflows. 8. Educate developers and system administrators about SSRF risks and secure coding practices related to URL handling.