CVE-2020-36456
📋 TL;DR
This vulnerability in the Rust toolshed crate allows Send trait misuse in CopyCell<T>, potentially enabling data races and memory corruption in concurrent Rust programs. It affects any Rust application using the vulnerable toolshed crate versions. Attackers could exploit this to cause undefined behavior, crashes, or potentially execute arbitrary code.
💻 Affected Systems
- toolshed Rust crate
📦 What is this software?
Toolshed by Toolshed Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise through memory corruption in concurrent Rust applications.
Likely Case
Application crashes, data corruption, or denial of service due to data races and undefined behavior in concurrent code.
If Mitigated
Limited impact if application doesn't use CopyCell<T> in concurrent contexts or has proper memory safety controls.
🎯 Exploit Status
Exploitation requires specific concurrent programming patterns and understanding of Rust's memory model.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: toolshed 0.8.0 and later
Vendor Advisory: https://rustsec.org/advisories/RUSTSEC-2020-0136.html
Restart Required: Yes
Instructions:
1. Update Cargo.toml to require toolshed >= 0.8.0
2. Run 'cargo update --package toolshed'
3. Rebuild and redeploy your Rust application
🔧 Temporary Workarounds
Avoid CopyCell<T> in concurrent code
allManually audit code to ensure CopyCell<T> is not used across thread boundaries
🧯 If You Can't Patch
- Isolate affected applications in containers or VMs with minimal privileges
- Implement strict input validation and monitoring for application crashes
🔍 How to Verify
Check if Vulnerable:
Check Cargo.lock for toolshed version < 0.8.0 and grep code for 'CopyCell' usageCheck Version:
grep toolshed Cargo.lock | head -1Verify Fix Applied:
Verify Cargo.lock shows toolshed >= 0.8.0 and run 'cargo audit'📡 Detection & Monitoring
Log Indicators:
- Application segmentation faults
- Rust panic messages related to concurrent access
Network Indicators:
- Unusual application restarts or crashes
SIEM Query:
source="application.log" AND ("segmentation fault" OR "thread panicked" OR "CopyCell")