CVE-2026-1813
📋 TL;DR
This vulnerability allows remote attackers to upload arbitrary files to bolo-solo blog systems due to insufficient validation in the FreeMarker template handler. Attackers can exploit this to upload malicious files like web shells or scripts. All users running bolo-solo versions up to 2.6.4 are affected.
💻 Affected Systems
- bolo-blog bolo-solo
📦 What is this software?
Bolo Solo by Adlered
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via web shell leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Unauthorized file upload leading to defacement, malware hosting, or limited server access depending on file execution context.
If Mitigated
Upload attempts blocked or quarantined with no successful exploitation.
🎯 Exploit Status
Exploit details are publicly available in the issue tracker and vulnerability databases.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch exists. Monitor the GitHub repository for updates or consider alternative software.
🔧 Temporary Workarounds
Restrict file upload extensions
allConfigure web server or application firewall to block uploads of executable file types.
# Example for Apache: Add to .htaccess
<FilesMatch "\.(php|jsp|asp|sh|exe)$">
Order Allow,Deny
Deny from all
</FilesMatch>
Disable FreeMarker template handler
linuxRemove or disable the vulnerable PicUploadProcessor component if not required.
# Remove or rename the vulnerable file
mv src/main/java/org/b3log/solo/bolo/pic/PicUploadProcessor.java PicUploadProcessor.java.disabled
🧯 If You Can't Patch
- Implement strict file upload validation at the network perimeter using WAF rules.
- Isolate the affected system in a restricted network segment with no internet access.
🔍 How to Verify
Check if Vulnerable:
Check if running bolo-solo version 2.6.4 or earlier and if PicUploadProcessor.java exists in the source.Check Version:
Check the pom.xml or build configuration for version information.Verify Fix Applied:
Verify that file upload functionality properly validates file types and extensions.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to /pic/upload endpoints
- Uploads of executable file types (.jsp, .php, .war)
Network Indicators:
- HTTP POST requests to upload endpoints with suspicious file content
SIEM Query:
source="web_server" AND (uri_path="/pic/upload" OR file_extension IN ("jsp", "php", "war"))