The vulnerability arises when the PDFService._markdown_to_html() function builds an HTML document by inserting user-controlled values, such as the research title or metadata key‑value pairs, directly into an f‑string without escaping. This permits an authenticated attacker to inject arbitrary HTML tags into the PDF export, which WeasyPrint processes. The injected HTML can be chained to trigger a Server‑Side Request Forgery (SSRF) that bypasses the application’s ssrf_validator guard, potentially allowing the attacker to access internal network resources or pull sensitive data from internal services.

The affected product is LearningCircuit’s Local‑Deep‑Research application. Versions earlier than 1.6.0 are vulnerable. Only users with authenticated access to construct research queries are impacted; unauthenticated users cannot exploit the flaw.

The CVSS score of 5 indicates a moderate severity. The EPSS score is not available, suggesting that the likelihood of exploitation is unknown or low, and the vulnerability is not currently listed in CISA’s KEV catalog. Exploitation requires authenticated access and depends on the application allowing arbitrary HTML in research queries. Successful exploitation would enable SSRF and potentially internal data exfiltration, but does not provide direct remote code execution.