CVE-2026-25139
📋 TL;DR
CVE-2026-25139 is an out-of-bounds read vulnerability in RIOT OS's 6LoWPAN stack that allows unauthenticated attackers to read adjacent memory or crash IoT devices by sending specially crafted packets. This affects all devices running RIOT version 2025.10 and earlier with the 6LoWPAN stack enabled. The vulnerability occurs when packets are cast to a struct without proper size validation.
💻 Affected Systems
- RIOT OS
📦 What is this software?
Riot by Riot Os
⚠️ Risk & Real-World Impact
Worst Case
Information disclosure of sensitive memory contents, potential device crash leading to denial of service, or possible remote code execution if combined with other vulnerabilities.
Likely Case
Device crashes causing denial of service, or memory leaks revealing adjacent data structures.
If Mitigated
Limited impact if network segmentation prevents external access, but internal attackers could still exploit.
🎯 Exploit Status
Exploitation requires ability to send or manipulate input packets to the vulnerable device.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-c8fh-23qr-97mc
Restart Required: Yes
Instructions:
No official patch available. Monitor RIOT GitHub repository for updates and apply when available.
🔧 Temporary Workarounds
Disable 6LoWPAN stack
allDisable the vulnerable 6LoWPAN stack if not required for device functionality.
Modify RIOT build configuration to exclude 6LoWPAN modules
Network segmentation
allIsolate vulnerable devices in separate network segments with strict firewall rules.
Configure firewall to block 6LoWPAN traffic from untrusted networks
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable devices
- Deploy network intrusion detection systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check RIOT OS version and verify 6LoWPAN stack is enabled. Vulnerable if version ≤ 2025.10 and using 6LoWPAN.Check Version:
Check RIOT version in source code or device firmware informationVerify Fix Applied:
When patch becomes available, verify version is > 2025.10 and test with packet fuzzing tools.📡 Detection & Monitoring
Log Indicators:
- Device crashes or restarts
- Memory access violation logs
- Unusual 6LoWPAN packet patterns
Network Indicators:
- Malformed 6LoWPAN packets
- Unusual packet sizes targeting vulnerable structs
SIEM Query:
Search for: device_type:"RIOT OS" AND (event:"crash" OR event:"memory_violation") AND protocol:"6LoWPAN"