CVE-2026-4947 is an improper access control vulnerability classified under CWE-284, discovered in Foxit Software Inc.'s electronic signature service hosted at na1.foxitesign.foxit.com. The flaw arises from insufficient authorization validation during the signing invitation acceptance process, specifically an insecure direct object reference (IDOR) condition. Attackers with network access and low privileges can manipulate user-supplied object identifiers in requests to access or modify resources they are not authorized to interact with. This manipulation can result in forged digital signatures, undermining the integrity and authenticity of documents processed through the platform. The vulnerability does not require user interaction but does require the attacker to have some level of privilege (PR:L). The CVSS 3.1 base score is 7.1, reflecting high severity due to the potential for confidentiality impact (unauthorized access to sensitive documents) and limited integrity impact (forged signatures), with no impact on availability. The vulnerability affects versions of the product released before March 26, 2026. Although no exploits have been reported in the wild, the nature of the flaw makes it a significant risk for organizations relying on Foxit's digital signature services. The root cause is inadequate authorization checks on referenced resources during request processing, allowing attackers to bypass access controls by altering object identifiers in API calls or web requests.

The primary impact of CVE-2026-4947 is on the confidentiality and integrity of documents undergoing electronic signature processes. Attackers exploiting this vulnerability can gain unauthorized access to sensitive documents or modify signing invitations, potentially forging signatures. This compromises the trustworthiness of signed documents, which can have severe legal and operational consequences for organizations relying on Foxit's platform for contract management, compliance, and secure document workflows. The vulnerability could lead to data breaches involving confidential information and undermine regulatory compliance efforts. Although availability is not affected, the reputational damage and potential financial losses from forged signatures and unauthorized data access are significant. Organizations in sectors such as legal, finance, healthcare, and government that depend heavily on digital signatures are particularly at risk. The ease of exploitation (network accessible with low privileges and no user interaction) increases the threat level, making timely remediation critical.

Organizations using Foxit’s na1.foxitesign.foxit.com service should immediately update to the patched version released after March 26, 2026. In addition to applying the official patch, organizations should implement strict authorization validation on all API endpoints handling signing invitations and related resources. This includes verifying user permissions against object identifiers server-side before processing requests. Employing robust input validation and object-level access controls can prevent IDOR exploitation. Monitoring and logging access to signing invitation endpoints can help detect suspicious activity. Where possible, implement multi-factor authentication and least privilege principles to reduce the risk of unauthorized access. Regular security assessments and penetration testing focused on access control mechanisms in digital signature workflows are recommended. Finally, educating users and administrators about the risks of forged signatures and suspicious document activities can aid early detection and response.