CVE-2025-43903
📋 TL;DR
This vulnerability in Poppler's PDF processing library allows attackers to forge digital signatures on PDF documents by bypassing signature verification for adbe.pkcs7.sha1 signatures. Systems using Poppler to process or validate PDF signatures are affected, particularly document management systems, PDF viewers, and applications that rely on Poppler for PDF parsing.
💻 Affected Systems
- Poppler
📦 What is this software?
Poppler by Freedesktop
⚠️ Risk & Real-World Impact
Worst Case
Attackers could create malicious PDF documents with forged valid signatures, potentially bypassing document authenticity checks in legal, financial, or compliance systems.
Likely Case
Attackers could create PDFs that appear legitimately signed, potentially tricking users into accepting fraudulent documents or bypassing document validation workflows.
If Mitigated
With proper signature validation at higher application layers and user awareness training, the impact is limited to specific Poppler-based processing workflows.
🎯 Exploit Status
Exploitation requires creating specially crafted PDF documents. No authentication is needed to trigger the vulnerability when processing such documents.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 25.04.0
Vendor Advisory: https://gitlab.freedesktop.org/poppler/poppler/-/commit/f1b9c830f145a0042e853d6462b2f9ca4016c669
Restart Required: No
Instructions:
1. Update Poppler to version 25.04.0 or later. 2. For Linux systems: Use package manager (apt, yum, etc.) to update poppler packages. 3. Recompile any applications statically linked to Poppler with the patched version.
🔧 Temporary Workarounds
Disable signature processing
allConfigure applications to disable PDF signature verification if not required
Application-specific configuration required
Use alternative PDF libraries
allSwitch to alternative PDF processing libraries that properly verify signatures
Implementation-specific
🧯 If You Can't Patch
- Implement application-layer signature validation using separate cryptographic libraries
- Scan all incoming PDFs with updated antivirus/EDR solutions before processing
🔍 How to Verify
Check if Vulnerable:
Check Poppler version: poppler --version or check installed package versionCheck Version:
poppler --version 2>/dev/null || dpkg -l | grep poppler || rpm -qa | grep popplerVerify Fix Applied:
Verify Poppler version is 25.04.0 or later and test with known vulnerable PDF samples📡 Detection & Monitoring
Log Indicators:
- Unexpected PDF processing errors
- Signature validation failures in application logs
Network Indicators:
- Unusual PDF document uploads to document processing systems
SIEM Query:
source="application_logs" AND ("PDF signature" OR "poppler") AND ("error" OR "failure")