CVE-2025-57248
📋 TL;DR
A null pointer dereference vulnerability in SumatraPDF 3.5.2 allows attackers to crash the application by tricking users into opening a malicious .djvu file. This affects all users running the vulnerable version of SumatraPDF. The crash occurs in the DataPool::has_data() function within libmupdf.dll.
💻 Affected Systems
- SumatraPDF
📦 What is this software?
Sumatrapdf by Sumatrapdfreader
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full system compromise if combined with other vulnerabilities or memory corruption techniques.
Likely Case
Denial of service through application crash when processing malicious files.
If Mitigated
Limited to application crash with no further impact if proper sandboxing or memory protections are in place.
🎯 Exploit Status
Exploitation requires user interaction to open malicious file. Simple crash PoC likely exists but not publicly documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://github.com/sumatrapdfreader/sumatrapdf/issues/5035
Restart Required: No
Instructions:
1. Monitor GitHub issue #5035 for updates. 2. Apply patch when released by SumatraPDF developers. 3. Update to fixed version once available.
🔧 Temporary Workarounds
Disable .djvu file association
windowsRemove SumatraPDF as default handler for .djvu files to prevent automatic opening
Control Panel > Default Programs > Set Default Programs > Select SumatraPDF > Choose defaults for this program > Uncheck .djvu
Use alternative PDF viewer
windowsTemporarily use a different PDF viewer until patch is available
🧯 If You Can't Patch
- Block .djvu files at email gateways and web proxies
- Educate users not to open .djvu files from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check SumatraPDF version in Help > About. If version is 3.5.2, system is vulnerable.Check Version:
sumatrapdf.exe --versionVerify Fix Applied:
Update to patched version when available and verify version number in Help > About.📡 Detection & Monitoring
Log Indicators:
- Application crash logs mentioning libmupdf.dll
- Windows Event Logs with Application Error for SumatraPDF.exe
Network Indicators:
- Downloads of .djvu files from suspicious sources
SIEM Query:
EventID=1000 AND SourceName=Application Error AND ProcessName=SumatraPDF.exe AND FaultModuleName=libmupdf.dll