CVE-2026-72544 in OpenSign
Summary
by MITRE • 08/11/2026
An integrity verification vulnerability in OpenSignLabs OpenSign through 2.37.0 allows unauthenticated remote attackers to forge document audit-trail entries via the triggerevent Parse cloud function. The function accepts viewer identity and IP address as caller-supplied parameters without authentication, allowing fabrication of arbitrary audit log entries. An attacker can tamper with the legal audit trail of any signed document, undermining non-repudiation.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical integrity verification flaw in OpenSignLabs OpenSign platform version 2.37.0 and earlier, classified under CWE-345 Insufficient Verification of Data Authenticity. The security weakness stems from the triggerevent Parse cloud function which lacks proper authentication mechanisms for processing viewer identity and IP address parameters. Attackers can exploit this by directly calling the function with arbitrary input values, bypassing the normal access controls that should validate user identities and verify legitimate session contexts. This design flaw fundamentally undermines the platform's ability to maintain authentic audit trails, creating a pathway for malicious actors to manipulate document history records without requiring any valid credentials or authorization.
The operational impact of this vulnerability extends beyond simple data manipulation into serious legal and compliance implications for organizations relying on OpenSign for document signing and verification processes. By forging audit trail entries, attackers can create false records indicating that documents were viewed or signed from unauthorized locations or by fictitious users, completely compromising the non-repudiation properties that digital signatures are designed to provide. This manipulation can occur without any authentication requirements, making it particularly dangerous as it allows unauthenticated remote exploitation. The vulnerability affects all signed documents within the affected system scope, potentially enabling attackers to establish false narratives about document access and modification history.
The attack vector leverages the Parse cloud function's lack of input validation and authentication checks, specifically targeting parameters that should normally be verified against legitimate user sessions or trusted sources. This represents a classic case of insecure direct object reference combined with insufficient authorization controls, aligning with ATT&CK technique T1566.002 for credential harvesting through spoofed identities. The vulnerability creates an attack surface where malicious actors can generate false audit entries that appear legitimate within the system's logging infrastructure, making detection particularly challenging. Organizations using OpenSign for compliance-critical applications face significant risks including potential legal disputes, regulatory violations, and compromised document authenticity guarantees.
Mitigation strategies should focus on implementing robust authentication mechanisms for all cloud functions that process audit trail data, requiring proper session validation and user authorization before accepting any viewer identity or IP address parameters. The system must enforce strict input validation and parameter sanitization to prevent arbitrary value injection into audit logs. Organizations should implement additional logging and monitoring of cloud function calls to detect anomalous patterns in audit trail modifications. Regular security assessments and penetration testing should verify that authentication mechanisms are properly enforced, while updates to the OpenSign platform should address this vulnerability through proper access control implementation and audit trail integrity verification processes.