CVE-2025-59946
📋 TL;DR
CVE-2025-59946 is a heap use-after-free vulnerability in NanoMQ MQTT broker caused by a data race condition in subscription information handling. This allows attackers to crash the broker service, potentially leading to denial of service. Organizations using NanoMQ versions before 0.24.2 for edge messaging are affected.
💻 Affected Systems
- NanoMQ MQTT Broker
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete broker crash leading to extended service disruption, potential data loss for in-flight messages, and possible remote code execution if heap corruption is leveraged.
Likely Case
Service crash and restart causing temporary MQTT messaging disruption, affecting IoT/edge device communication.
If Mitigated
Service restart with minimal data loss if proper monitoring and auto-restart mechanisms are in place.
🎯 Exploit Status
Exploitation requires triggering a data race condition which may be timing-dependent but doesn't require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.24.2
Vendor Advisory: https://github.com/nanomq/nanomq/security/advisories/GHSA-xg37-23w7-72p5
Restart Required: Yes
Instructions:
1. Download NanoMQ 0.24.2 or later from official repository. 2. Stop the running NanoMQ service. 3. Replace the binary with the patched version. 4. Restart the NanoMQ service.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to NanoMQ broker to trusted networks only
Rate Limiting
linuxImplement connection and subscription rate limiting to reduce race condition triggers
iptables -A INPUT -p tcp --dport 1883 -m limit --limit 60/min --limit-burst 100 -j ACCEPT
🧯 If You Can't Patch
- Implement network-level protections like firewalls and intrusion prevention systems
- Deploy redundant NanoMQ instances with load balancing to maintain service during crashes
🔍 How to Verify
Check if Vulnerable:
Check NanoMQ version with 'nanomq --version' or examine binary metadataCheck Version:
nanomq --versionVerify Fix Applied:
Confirm version is 0.24.2 or later and monitor for crash events in logs📡 Detection & Monitoring
Log Indicators:
- Segmentation fault
- heap corruption
- use-after-free
- abnormal termination
- core dump generation
Network Indicators:
- Unusual subscription patterns
- rapid connection/disconnection attempts
- MQTT protocol anomalies
SIEM Query:
source="nanomq.log" AND ("segmentation fault" OR "heap" OR "abort" OR "core dumped")