CVE-2025-0781
📋 TL;DR
CVE-2025-0781 is a sandbox escape vulnerability in FlightGear's Nasal scripting engine that allows attackers to write arbitrary files to any location the user has OS-level permissions to modify. This affects FlightGear flight simulator users who run untrusted Nasal scripts. The vulnerability stems from improper authorization (CWE-863) in the sandbox implementation.
💻 Affected Systems
- FlightGear Flight Simulator
- SimGear
📦 What is this software?
Simgear by Flightgear
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary file writes leading to privilege escalation, malware installation, or data destruction.
Likely Case
Local file system manipulation, configuration file corruption, or malicious script persistence within the FlightGear environment.
If Mitigated
Limited impact if scripts run with minimal user privileges and in isolated environments.
🎯 Exploit Status
Exploitation requires the victim to execute a malicious Nasal script. No public exploit code is available as of the advisory dates.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FlightGear commit ad37afce28083fad7f79467b3ffdead753584358 and later, SimGear commit 5bb023647114267141a7610e8f1ca7d6f4f5a5a8 and later
Vendor Advisory: https://gitlab.com/flightgear/flightgear/-/issues/3025
Restart Required: No
Instructions:
1. Update FlightGear to latest version from official repository. 2. Update SimGear to latest version. 3. Rebuild from source if using custom builds. 4. For Debian systems, apply security updates via apt.
🔧 Temporary Workarounds
Disable Nasal Script Execution
allPrevent execution of Nasal scripts entirely to block exploitation.
Modify FlightGear configuration to disable Nasal scripting or remove Nasal script support
Run with Restricted Permissions
allRun FlightGear with minimal user privileges to limit file write damage.
Run as non-privileged user, use chroot or container isolation
🧯 If You Can't Patch
- Run FlightGear in a sandboxed environment (Docker container, VM) with restricted file system access
- Implement strict access controls on FlightGear configuration and data directories
🔍 How to Verify
Check if Vulnerable:
Check FlightGear version against vulnerable commits. For source builds, verify commit hash is before ad37afce28083fad7f79467b3ffdead753584358.Check Version:
flightgear --version or check git commit hash in source directoryVerify Fix Applied:
Confirm FlightGear commit includes ad37afce28083fad7f79467b3ffdead753584358 or later. For packaged versions, check with package manager.📡 Detection & Monitoring
Log Indicators:
- Unusual file write operations from FlightGear process
- Nasal script execution errors or warnings
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Process:flightgear AND (FileCreate OR FileWrite) AND Path NOT IN [expected FlightGear directories]🔗 References
- https://gitlab.com/flightgear/flightgear/-/commit/ad37afce28083fad7f79467b3ffdead753584358
- https://gitlab.com/flightgear/flightgear/-/issues/3025
- https://gitlab.com/flightgear/simgear/-/commit/5bb023647114267141a7610e8f1ca7d6f4f5a5a8
- https://lists.debian.org/debian-lts-announce/2025/01/msg00028.html
- https://lists.debian.org/debian-lts-announce/2025/01/msg00029.html
