CVE-2021-28306
📋 TL;DR
This vulnerability in the Rust fltk crate allows a NULL pointer dereference when using a multi label type with a nonexistent image. This can cause application crashes or potentially allow arbitrary code execution. It affects Rust applications using the fltk crate before version 0.15.3.
💻 Affected Systems
- fltk Rust crate
📦 What is this software?
Fltk by Fltk Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if combined with other vulnerabilities or memory corruption techniques.
Likely Case
Application crash (denial of service) when processing malformed input or invalid image data.
If Mitigated
Application crash with limited impact if proper sandboxing and privilege separation are implemented.
🎯 Exploit Status
Exploitation requires specific conditions: using multi label types with nonexistent images. No public exploits have been documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.15.3 and later
Vendor Advisory: https://rustsec.org/advisories/RUSTSEC-2021-0038.html
Restart Required: Yes
Instructions:
1. Update Cargo.toml to require fltk >= 0.15.3. 2. Run 'cargo update' to fetch the patched version. 3. Rebuild and redeploy your application.
🔧 Temporary Workarounds
Avoid multi label with images
allTemporarily avoid using multi label types with image functionality until patched.
Image validation
allImplement validation to ensure images exist before using them with multi label types.
🧯 If You Can't Patch
- Implement input validation to prevent processing of invalid or nonexistent image files.
- Run application with reduced privileges and memory protection mechanisms (ASLR, DEP).
🔍 How to Verify
Check if Vulnerable:
Check Cargo.lock or run 'cargo tree | grep fltk' to see if fltk version is below 0.15.3.Check Version:
cargo tree | grep fltkVerify Fix Applied:
Confirm fltk version is 0.15.3 or higher in Cargo.lock after update.📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults or access violation errors
- Error logs mentioning fltk or image loading failures
SIEM Query:
Application logs containing 'segmentation fault', 'access violation', or 'fltk' error messages