CVE-2020-28626
📋 TL;DR
This vulnerability in CGAL library allows remote code execution through specially crafted polygon files. Attackers can exploit out-of-bounds read and type confusion vulnerabilities in Nef polygon parsing to execute arbitrary code. Systems using CGAL for computational geometry operations are affected.
💻 Affected Systems
- CGAL (Computational Geometry Algorithms Library)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the affected system, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Application crash leading to denial of service, with potential for limited code execution depending on application context and memory layout.
If Mitigated
Application crash without code execution if memory protections (ASLR, DEP) are effective, but still causing service disruption.
🎯 Exploit Status
Exploitation requires crafting malicious polygon files and getting them processed by vulnerable CGAL applications. No public exploit code has been identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: CGAL-5.1.2 and later
Vendor Advisory: https://www.cgal.org/
Restart Required: Yes
Instructions:
1. Update CGAL to version 5.1.2 or later. 2. Recompile any applications using CGAL. 3. Restart affected services. 4. For Linux distributions, use package manager: 'sudo apt update && sudo apt upgrade libcgal-dev' (Debian/Ubuntu) or 'sudo yum update cgal' (RHEL/CentOS).
🔧 Temporary Workarounds
Disable Nef polygon processing
allModify applications to avoid using CGAL's Nef polygon parsing functionality
# Modify application code to avoid Nef polygon parsing
# Recompile application after code changes
Input validation
allImplement strict validation of polygon files before passing to CGAL
# Add file validation logic in application
# Reject malformed or suspicious polygon files
🧯 If You Can't Patch
- Network segmentation to isolate systems using CGAL
- Implement strict file upload controls and validation for polygon files
🔍 How to Verify
Check if Vulnerable:
Check CGAL version: 'pkg-config --modversion cgal' or check installed packages for libcgal versionCheck Version:
pkg-config --modversion cgal || dpkg -l | grep libcgal || rpm -qa | grep cgalVerify Fix Applied:
Verify CGAL version is 5.1.2 or later: 'pkg-config --modversion cgal' should return 5.1.2+📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing polygon files
- Memory access violation errors in application logs
- Unexpected process termination of CGAL applications
Network Indicators:
- Unusual file uploads to applications using CGAL
- Network traffic spikes followed by application crashes
SIEM Query:
source="application.log" AND ("segmentation fault" OR "access violation" OR "out of bounds") AND process="*cgal*"🔗 References
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
