Addressed a potential insecure direct object reference (IDOR) vulnerability in the signing invitation acceptance process. Under certain conditions, this issue could have allowed an attacker to access or modify unauthorized resources by manipulating user-supplied object identifiers, potentially leading to forged signatures and compromising the integrity and authenticity of documents undergoing the signing process. The issue was caused by insufficient authorization validation on referenced resources during request processing.

URL parameters are directly embedded into JavaScript code or HTML attributes without proper encoding or sanitization. This allows attackers to inject arbitrary scripts when an authenticated user visits a crafted link.

This issue affects na1.foxitesign.foxit.com: before 2026‑01‑16.