CVE-2025-67825
📋 TL;DR
Nitro PDF Pro for Windows before version 14.42.0.34 displays signer information from unverified PDF fields instead of verified certificate subjects. This allows attackers to create PDFs that show misleading signer details, potentially tricking users into trusting fraudulent documents. Only users of vulnerable Nitro PDF Pro versions on Windows are affected.
💻 Affected Systems
- Nitro PDF Pro for Windows
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could forge digital signatures to make malicious PDFs appear legitimate, leading to financial fraud, data theft, or malware installation.
Likely Case
Users might be tricked into opening phishing documents or accepting fraudulent contracts due to misleading signature information.
If Mitigated
With proper verification procedures and updated software, users would see correct signer information from verified certificates.
🎯 Exploit Status
Exploitation requires creating a specially crafted PDF with manipulated signature fields. User interaction (opening the PDF) is required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 14.42.0.34 and later
Vendor Advisory: https://www.gonitro.com/documentation/release-notes
Restart Required: Yes
Instructions:
1. Open Nitro PDF Pro. 2. Go to Help > Check for Updates. 3. Follow prompts to download and install version 14.42.0.34 or later. 4. Restart the application.
🔧 Temporary Workarounds
Disable automatic PDF opening
windowsConfigure system to not automatically open PDFs in Nitro PDF Pro
Use alternative PDF viewer
windowsTemporarily use a different PDF application for signed documents
🧯 If You Can't Patch
- Train users to manually verify digital signatures through certificate properties
- Implement policy requiring secondary verification of signed documents via email or phone
🔍 How to Verify
Check if Vulnerable:
Open Nitro PDF Pro, go to Help > About, check if version is below 14.42.0.34Check Version:
Not applicable - check via application GUIVerify Fix Applied:
After updating, open a test PDF with digital signature and verify signer information matches certificate subject📡 Detection & Monitoring
Log Indicators:
- Multiple failed signature validations
- Unusual PDF file access patterns
Network Indicators:
- Downloads of PDFs from untrusted sources followed by signature verification
SIEM Query:
EventID=4688 AND ProcessName='NitroPDF.exe' AND CommandLine LIKE '%.pdf%'