CVE-2023-36998
📋 TL;DR
CVE-2023-36998 is a stack-based buffer overflow vulnerability in NextEPC MME's Emergency Number List decoding. Attackers with cellphone connections to base stations managed by the MME can send specially crafted NAS messages to overwrite the stack with arbitrary bytes without authentication. This affects NextEPC MME deployments in LTE core networks.
💻 Affected Systems
- NextEPC MME
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete compromise of the MME, potential lateral movement within the LTE core network, and service disruption for all connected mobile devices.
Likely Case
Denial of service causing MME crash and temporary loss of mobile connectivity for affected base stations, potentially requiring manual restart.
If Mitigated
If network segmentation and proper firewall rules are in place, exploitation may be limited to denial of service without lateral movement.
🎯 Exploit Status
Exploitation requires understanding of LTE NAS protocol and ability to send crafted messages to the MME via a base station connection.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in commit a8492c9c5bc0a66c6999cb5a263545b32a4109df
Vendor Advisory: http://nextepc.com
Restart Required: Yes
Instructions:
1. Update to the latest NextEPC version containing commit a8492c9c5bc0a66c6999cb5a263545b32a4109df. 2. Restart the MME service. 3. Verify the fix is applied.
🔧 Temporary Workarounds
Network Segmentation
allIsolate MME from untrusted networks and implement strict firewall rules to limit access to only authorized base stations.
🧯 If You Can't Patch
- Implement strict network access controls to limit MME exposure to only trusted base stations using firewall rules.
- Deploy intrusion detection systems to monitor for anomalous NAS messages and emergency number list patterns.
🔍 How to Verify
Check if Vulnerable:
Check NextEPC MME version. If version <= 1.0.1, the system is vulnerable.Check Version:
Check NextEPC documentation or configuration files for version information.Verify Fix Applied:
Verify the installed version includes commit a8492c9c5bc0a66c6999cb5a263545b32a4109df or is newer than 1.0.1.📡 Detection & Monitoring
Log Indicators:
- MME crash logs
- Unexpected emergency number list decoding errors
- Abnormal NAS message processing failures
Network Indicators:
- Unusually large emergency number list values in NAS messages
- Multiple connection attempts with malformed NAS messages from single sources
SIEM Query:
Search for MME process crashes or emergency number list decoding errors in system logs.