CVE-2026-3778 is a vulnerability categorized under CWE-674 (Uncontrolled Recursion) found in Foxit Software Inc.'s Foxit PDF Editor. The vulnerability exists because the application does not detect or prevent cyclic references between PDF objects when processing JavaScript embedded in PDFs. Attackers can craft PDF documents where pages and annotations reference each other in a loop, creating cyclic object references. When such a document is passed to APIs that perform deep traversal of the PDF structure—such as SOAP APIs—the recursion is uncontrolled, leading to stack exhaustion. This results in application crashes and denial-of-service conditions. The affected versions include Foxit PDF Editor 2025.3 and earlier, 14.0.2 and earlier, and 13.2.2 and earlier. The CVSS v3.1 score is 6.2 (medium severity), with an attack vector of local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), and high impact on availability (A:H). There are no known exploits in the wild currently, and no patches have been linked yet. The vulnerability primarily threatens availability by causing application crashes during PDF processing, which could disrupt workflows relying on Foxit PDF Editor for document handling.

The primary impact of CVE-2026-3778 is denial of service due to application crashes caused by stack exhaustion from uncontrolled recursion. Organizations relying on Foxit PDF Editor for document processing, especially those automating PDF handling via APIs like SOAP, may experience service interruptions or downtime. This can disrupt business operations, delay document workflows, and potentially cause loss of productivity. Since the vulnerability does not affect confidentiality or integrity, data breaches or unauthorized data modifications are not a direct concern. However, repeated crashes could lead to system instability or require manual intervention to recover. In environments where Foxit PDF Editor is integrated into critical document management systems, this vulnerability could have a significant operational impact. The requirement for local access to exploit limits remote attack potential, but insider threats or compromised endpoints could leverage this flaw to cause disruption.

1. Upgrade Foxit PDF Editor to the latest version once patches addressing CVE-2026-3778 are released by Foxit Software Inc. 2. Until patches are available, implement input validation to detect and reject PDFs containing cyclic object references or suspicious JavaScript code. 3. Limit the recursion depth in PDF processing APIs, especially when using SOAP or similar deep traversal methods, to prevent stack exhaustion. 4. Employ sandboxing or isolated environments for processing untrusted PDF documents to contain potential crashes without affecting critical systems. 5. Monitor application logs and system stability for signs of crashes or abnormal behavior during PDF handling. 6. Educate users and administrators about the risks of opening PDFs from untrusted sources and enforce strict document handling policies. 7. Consider disabling JavaScript execution within PDFs if not required for business processes to reduce attack surface. 8. Conduct regular security assessments and penetration testing focused on document processing workflows to identify similar vulnerabilities.