CVE-2026-69078 in CTI-Transmute
Summary
by MITRE • 08/03/2026
CTI-Transmute is affected by a server-side request forgery vulnerability in the evaluation report PDF-generation functionality.
User-controlled CTI content, including conversion names, descriptions, and comments, is converted from Markdown to HTML and rendered as a PDF using WeasyPrint. Before the patch, the renderer used WeasyPrint’s default URL-fetching behavior without restricting the protocols or destinations that could be referenced by the generated HTML.
An attacker able to supply content included in an evaluation report could inject crafted resource references using schemes such as http://, https://, or file://. When the report was rendered, CTI-Transmute could fetch these resources using the application server’s network connectivity and filesystem privileges.
Successful exploitation could allow an attacker to:
* access services available only from the CTI-Transmute server or its internal network; * probe internal hosts and service endpoints; * retrieve local files readable by the application process; and * expose fetched content through the generated PDF, depending on the referenced resource type and rendering context.
The vulnerability is corrected by providing WeasyPrint with a restrictive URL fetcher that permits only self-contained data: URIs. The externally hosted Google Fonts stylesheet was also removed so that PDF generation performs no intentional network or filesystem fetches.
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Analysis
by VulDB Data Team • 08/03/2026
This server-side request forgery vulnerability in CTI-Transmute represents a critical security flaw that leverages the application's PDF generation functionality to execute unauthorized network requests. The vulnerability exists within the evaluation report PDF-generation process where user-controlled CTI content including conversion names, descriptions, and comments undergoes Markdown to HTML conversion before being rendered as PDFs using WeasyPrint. The flaw stems from the absence of protocol and destination restrictions in the default WeasyPrint URL-fetching behavior, creating an attack surface that allows malicious actors to inject crafted resource references into the HTML rendering pipeline.
The technical implementation of this vulnerability enables attackers to exploit the application server's network connectivity and filesystem privileges through various protocol schemes including http://, https://, and file://. When the report is rendered, these injected references cause CTI-Transmute to fetch external resources using the server's elevated permissions, effectively bypassing normal network segmentation and access controls. This creates a pathway for attackers to leverage the application server as a pivot point for internal reconnaissance and data exfiltration activities.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass active network reconnaissance and potential privilege escalation scenarios. Attackers can probe internal hosts and service endpoints that would normally be inaccessible from external networks, mapping the internal attack surface and identifying vulnerable systems. Additionally, the ability to retrieve local files readable by the application process provides attackers with access to potentially sensitive data stored on the server. The exposure of fetched content through generated PDFs creates an indirect exfiltration mechanism where malicious payloads can be embedded within seemingly legitimate documents, complicating detection and forensic analysis.
This vulnerability aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities, and demonstrates characteristics consistent with ATT&CK technique T1071.004 for application layer protocol usage. The remediation approach implemented by the developers involves configuring WeasyPrint with a restrictive URL fetcher that permits only self-contained data URIs, effectively eliminating external resource fetching capabilities during PDF generation. The additional measure of removing externally hosted Google Fonts stylesheet ensures that PDF generation performs no intentional network or filesystem fetches, creating a more secure and isolated processing environment.
The patch addresses fundamental security principles by implementing least privilege access controls and defense in depth strategies. By restricting URL fetching to only self-contained data URIs, the fix eliminates the attack vector while maintaining the core functionality of document generation. This approach prevents attackers from leveraging the application server's network capabilities for malicious purposes and ensures that PDF generation remains a contained process without unintended external dependencies. The solution represents a comprehensive remediation that addresses both the immediate vulnerability and potential future similar issues through restrictive configuration practices.