CVE-2025-50361
📋 TL;DR
A buffer overflow vulnerability exists in SmallBASIC's SDL implementation that could allow attackers to crash the application or potentially leak sensitive information. This affects users running SmallBASIC community edition with SDL before version 12_28. The vulnerability is triggered through the main.cpp function and requires user interaction or malicious input.
💻 Affected Systems
- SmallBASIC community edition with SDL
📦 What is this software?
Smallbasic by Smallbasic
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if combined with other vulnerabilities, though unlikely given the CVSS score and CWE type.
Likely Case
Application crash (denial of service) and potential memory content leakage revealing sensitive information from the application's memory space.
If Mitigated
Application instability or unexpected termination with minimal data exposure if input validation is enforced externally.
🎯 Exploit Status
Public GitHub repository exists with exploit details. Exploitation requires feeding malicious input to the vulnerable function, which could be done through crafted BASIC programs or direct memory manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v12_28 or later, commit sha:298a1d495355959db36451e90a0ac74bcc5593fe and beyond
Vendor Advisory: https://github.com/smallbasic/SmallBASIC
Restart Required: Yes
Instructions:
1. Download latest SmallBASIC from official GitHub repository. 2. Replace existing installation. 3. Restart any running SmallBASIC instances. 4. Recompile any custom builds using updated source code.
🔧 Temporary Workarounds
Disable SDL backend
allRun SmallBASIC with console-only or alternative graphics backends if available
smallbasic --no-sdl
smallbasic --console
Input validation wrapper
linuxCreate wrapper script that validates input before passing to SmallBASIC
#!/bin/bash
# Validate input length
if [ ${#1} -gt 1000 ]; then echo 'Input too long'; exit 1; fi
smallbasic "$1"
🧯 If You Can't Patch
- Restrict SmallBASIC execution to trusted users only and monitor for abnormal crashes
- Implement application whitelisting to prevent execution of untrusted SmallBASIC scripts
🔍 How to Verify
Check if Vulnerable:
Check SmallBASIC version: smallbasic --version. If output shows version earlier than 12_28 or commit hash earlier than 298a1d495355959db36451e90a0ac74bcc5593fe, you are vulnerable.Check Version:
smallbasic --versionVerify Fix Applied:
After update, run smallbasic --version and confirm version is 12_28 or later. Test with known exploit payloads from GitHub repository to ensure no crash occurs.📡 Detection & Monitoring
Log Indicators:
- Multiple SmallBASIC process crashes with segmentation faults
- Abnormal memory access errors in system logs
- Large input buffers being passed to SmallBASIC
Network Indicators:
- N/A - primarily local exploitation
SIEM Query:
process_name:"smallbasic" AND (event_type:"crash" OR exit_code:139 OR exit_code:-1073741819)