CVE-2021-31996
📋 TL;DR
This vulnerability in the algorithmica Rust crate allows double-free memory corruption in the merge_sort::merge() function. Attackers can potentially execute arbitrary code or cause denial of service by exploiting this memory management flaw. Any Rust application using vulnerable versions of the algorithmica crate is affected.
💻 Affected Systems
- algorithmica Rust crate
📦 What is this software?
Algorithmica by Algorithmica Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash or denial of service due to memory corruption, potentially leading to data loss or service disruption.
If Mitigated
Contained application crash without privilege escalation if proper sandboxing and memory protections are in place.
🎯 Exploit Status
Exploitation requires triggering the specific merge function with crafted input, making it dependent on application usage patterns.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to algorithmica crate version after 2021-03-07
Vendor Advisory: https://rustsec.org/advisories/RUSTSEC-2021-0053.html
Restart Required: Yes
Instructions:
1. Update Cargo.toml to use algorithmica version > 0.1.0 (post-2021-03-07). 2. Run 'cargo update algorithmica'. 3. Rebuild and redeploy your application. 4. Restart affected services.
🔧 Temporary Workarounds
Remove algorithmica dependency
allTemporarily remove or replace the algorithmica crate with alternative sorting implementations
cargo remove algorithmica
Disable merge_sort usage
allModify code to avoid calling merge_sort::merge() function
🧯 If You Can't Patch
- Implement strict input validation to prevent triggering the vulnerable merge function
- Deploy memory protection mechanisms like ASLR and DEP to reduce exploitation impact
🔍 How to Verify
Check if Vulnerable:
Check Cargo.lock for algorithmica version <= 0.1.0 (2021-03-07)Check Version:
grep algorithmica Cargo.lockVerify Fix Applied:
Verify algorithmica version > 0.1.0 in Cargo.lock after update📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory corruption errors in Rust panic logs
- Unexpected process termination
Network Indicators:
- Unusual traffic patterns to endpoints using sorting functionality
SIEM Query:
process.name: "your_application" AND (event.type: "crash" OR error.message: "*double free*" OR error.message: "*memory corruption*")