CVE-2020-28601
📋 TL;DR
CVE-2020-28601 is a critical out-of-bounds read vulnerability in CGAL's Nef polygon-parsing functionality that can lead to remote code execution. Attackers can exploit this by providing malicious input to trigger memory corruption. This affects systems using CGAL library versions 5.1.1 and earlier for computational geometry operations.
💻 Affected Systems
- CGAL (Computational Geometry Algorithms Library)
📦 What is this software?
Computational Geometry Algorithms Library by Cgal
View all CVEs affecting Computational Geometry Algorithms Library →
Fedora by Fedoraproject
Fedora by Fedoraproject
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution with attacker gaining complete control of 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 information disclosure through memory leaks that could aid further exploitation.
If Mitigated
Application crash without code execution if memory protections like ASLR are effective, but still causing service disruption.
🎯 Exploit Status
Exploitation requires crafting malicious polygon data to trigger the OOB read, which could lead to memory corruption and potential code execution.
🛠️ 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/Fedora).
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation for polygon data before passing to CGAL functions
Disable Nef Polygon Parsing
allIf not required, disable or avoid using Nef polygon-parsing functionality in CGAL
🧯 If You Can't Patch
- Network segmentation to isolate systems using CGAL
- Implement strict input validation and sanitization for all polygon data inputs
🔍 How to Verify
Check if Vulnerable:
Check CGAL version: 'pkg-config --modversion cgal' or check installed packages: 'dpkg -l | grep cgal' (Debian) or 'rpm -qa | grep -i cgal' (RHEL/Fedora). Version 5.1.1 or earlier is vulnerable.Check Version:
pkg-config --modversion cgalVerify Fix Applied:
Verify CGAL version is 5.1.2 or later using version check commands. Test polygon parsing functionality with known safe inputs.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory access violation errors
- Unexpected termination of CGAL-based applications
Network Indicators:
- Unusual network traffic to/from applications using CGAL
- Large or malformed polygon data transfers
SIEM Query:
source="application_logs" AND ("segmentation fault" OR "memory violation" OR "CGAL")🔗 References
- https://lists.debian.org/debian-lts-announce/2021/05/msg00002.html
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E4J344OKKDLPRN422OYRR46HDEN6MM6P/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NB5SF5OJR2DSV7CC6U7FVW5VJSJO5EKV/
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
- https://lists.debian.org/debian-lts-announce/2021/05/msg00002.html
- https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E4J344OKKDLPRN422OYRR46HDEN6MM6P/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NB5SF5OJR2DSV7CC6U7FVW5VJSJO5EKV/
- https://security.gentoo.org/glsa/202305-34
- https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225
