CVE-2026-25556
📋 TL;DR
MuPDF versions 1.23.0 through 1.27.0 contain a double-free vulnerability in the barcode decoding functionality. When processing specially crafted input that triggers a rendering error, the heap can become corrupted, leading to application crashes. This affects any application using MuPDF's barcode decoding feature with vulnerable versions.
💻 Affected Systems
- MuPDF
📦 What is this software?
Mupdf by Artifex
⚠️ Risk & Real-World Impact
Worst Case
Heap corruption could potentially lead to remote code execution if an attacker can control memory layout and exploit the corruption.
Likely Case
Application crash (denial of service) when processing malicious PDF files containing crafted barcodes.
If Mitigated
No impact if barcode decoding is disabled or if vulnerable versions aren't used.
🎯 Exploit Status
Exploitation requires crafting a PDF that triggers a rendering error during barcode decoding. No public exploit code has been observed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit d4743b6092d513321c23c6f7fe5cff87cde043c1 and later versions
Vendor Advisory: https://bugs.ghostscript.com/show_bug.cgi?id=709029
Restart Required: Yes
Instructions:
1. Update MuPDF to version after commit d4743b6092d513321c23c6f7fe5cff87cde043c1. 2. Rebuild any applications using MuPDF. 3. Restart affected services.
🔧 Temporary Workarounds
Disable barcode decoding
allDisable MuPDF's barcode decoding feature to prevent triggering the vulnerability
Configure application to not use fz_decode_barcode_from_display_list() or disable barcode support
🧯 If You Can't Patch
- Disable barcode decoding functionality in all applications using MuPDF
- Implement strict input validation and sandboxing for PDF processing
🔍 How to Verify
Check if Vulnerable:
Check MuPDF version and verify if barcode decoding is enabled in your application configurationCheck Version:
mupdf --version or check library version in applicationVerify Fix Applied:
Verify MuPDF version is after commit d4743b6092d513321c23c6f7fe5cff87cde043c1 and test barcode decoding with known problematic files📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing PDF files
- Error messages related to fz_fill_pixmap_from_display_list or barcode decoding
Network Indicators:
- Unusual PDF uploads to document processing services
SIEM Query:
search 'MuPDF crash' OR 'barcode decoding error' in application logs