CVE-2025-9809
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code by providing a specially crafted .cue file with an overly long file path. When processed by libretro-common, the path is copied into a fixed-size buffer using memcpy, causing an out-of-bounds write. All platforms using vulnerable versions of libretro-common are affected.
💻 Affected Systems
- libretro-common
- RetroArch
- other libretro-based emulators
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to install malware, steal data, or create persistent backdoors.
Likely Case
Remote code execution leading to service disruption, data theft, or lateral movement within the network.
If Mitigated
Denial of service or application crash if exploit fails, but system remains intact.
🎯 Exploit Status
Exploitation requires supplying a crafted .cue file; no authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check latest libretro-common repository for fix commit
Vendor Advisory: https://github.com/libretro/libretro-common/issues/222
Restart Required: Yes
Instructions:
1. Update libretro-common to latest version from GitHub. 2. Rebuild any applications using the library. 3. Restart affected services.
🔧 Temporary Workarounds
Input validation for .cue files
allReject .cue files with file paths exceeding PATH_MAX_LENGTH before processing.
Disable CDFS parsing
allIf not needed, disable CDFS/CD image support in affected applications.
🧯 If You Can't Patch
- Implement strict file upload controls to block .cue files from untrusted sources.
- Use application sandboxing or containerization to limit exploit impact.
🔍 How to Verify
Check if Vulnerable:
Check if application uses libretro-common and processes .cue files; review source code for vulnerable memcpy at line 471 in cdfs.c.Check Version:
Check libretro-common version in build configuration or repository commit hash.Verify Fix Applied:
Verify the fix implements proper bounds checking for file path length in cdfs_open_cue_track function.📡 Detection & Monitoring
Log Indicators:
- Application crashes when processing .cue files
- Unusual memory access errors in logs
Network Indicators:
- Unexpected .cue file transfers to vulnerable systems
SIEM Query:
Search for process crashes related to libretro applications or .cue file processing anomalies.