CVE-2025-59802: HIGH Severity Signature Spoofing in Foxit PDF Editor/Reader | Secably CVE Database

Summary

CVE-2025-59802 is a HIGH severity vulnerability affecting Foxit PDF Editor and Reader before versions 2025.2.1, 14.0.1, and 13.2.1. This vulnerability allows for signature spoofing by manipulating Optional Content Groups (OCG) after a document has been digitally signed, potentially leading to a mismatch between the signed content and what the verifier sees.

Technical Details

CVE-2025-59802 arises from the improper handling of Optional Content Groups (OCG) within Foxit PDF Editor and Reader. When OCGs are supported, the 'state' property of an OCG, which determines its visibility, is runtime-only and is not included in the digital signature computation buffer. This means that an attacker can leverage JavaScript or PDF triggers to dynamically change the visibility of OCG content *after* the document has been digitally signed (Post-Sign). By manipulating the visibility of content within OCGs, an attacker can alter the visual representation of the PDF without invalidating the digital signature. This allows for the creation of malicious PDFs where the displayed content differs significantly from the content that was originally signed, undermining the trustworthiness of the digital signature. The vulnerability relies on the fact that the signature verification process does not account for the dynamic state of OCGs.

The attack vector involves crafting a PDF document containing OCGs and JavaScript or PDF triggers designed to modify the visibility of these OCGs after the document is signed. A user opens the PDF, the JavaScript or PDF triggers execute, and the OCG content is altered, changing the document's appearance. The signature remains valid because the initial signature computation did not include the OCG state.

Affected Products and Versions

The following Foxit PDF Editor and Reader versions are affected by CVE-2025-59802:

Foxit PDF Editor and Reader versions prior to 2025.2.1
Foxit PDF Editor and Reader versions prior to 14.0.1
Foxit PDF Editor and Reader versions prior to 13.2.1

Impact Assessment

Successful exploitation of CVE-2025-59802 can have significant consequences, as it allows for the creation of digitally signed documents with misleading or malicious content. This can lead to:

Financial Fraud: A signed invoice could be altered to change the payment amount or recipient details.
Legal Disputes: Signed contracts could be modified to favor one party over another.
Reputational Damage: Organizations relying on digital signatures for document integrity could suffer reputational damage if their signed documents are compromised.
Malware Distribution: A signed document could be altered to include malicious links or embedded malware.

Remediation

Immediate Actions

Upgrade Foxit PDF Editor/Reader: Upgrade to versions 2025.2.1, 14.0.1, or 13.2.1 or later.
Verify Signatures Carefully: Exercise caution when verifying digital signatures, especially if the document's content appears suspicious.
Disable JavaScript (Temporary): As a temporary measure, consider disabling JavaScript execution within Foxit PDF Editor/Reader, although this may affect the functionality of some PDF documents.

Long-term Solutions

Implement Robust Signature Verification: Ensure that signature verification processes account for dynamic content and potential manipulation of OCGs.
Monitor for Suspicious Activity: Implement monitoring mechanisms to detect suspicious PDF documents or unusual behavior within Foxit PDF Editor/Reader.

References

Foxit Security Bulletins

Detection & Scanning

Detecting CVE-2025-59802 requires careful analysis of PDF documents and their digital signatures. Look for discrepancies between the signed content and the displayed content, especially in documents containing Optional Content Groups (OCGs) and JavaScript. Manual inspection or specialized PDF analysis tools may be necessary.

Scan Your Website

Secably AI Scanner can detect this and 50+ other vulnerabilities automatically.

Start Free Scan