CVE-2026-25139 in RIOT
Summary
by MITRE • 02/04/2026
RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. In version 2025.10 and prior, multiple out-of-bounds read allow any unauthenticated user, with ability to send or manipulate input packets, to read adjacent memory locations, or crash a vulnerable device running the 6LoWPAN stack. The received packet is cast into a sixlowpan_sfr_rfrag_t struct and dereferenced without validating the packet is large enough to contain the struct object. At time of publication, no known patch exists.
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Analysis
by VulDB Data Team • 02/20/2026
The vulnerability identified as CVE-2026-25139 affects RIOT OS version 2025.10 and earlier, a popular open-source operating system designed specifically for Internet of Things and embedded devices. This critical flaw resides within the 6LoWPAN stack implementation, which enables IPv6 communication over low-power wireless personal area networks. The vulnerability stems from inadequate input validation during packet processing, creating a dangerous condition where attackers can manipulate network traffic to exploit memory access violations. The 6LoWPAN protocol is fundamental to IoT device connectivity, making this vulnerability particularly concerning given the widespread deployment of RIOT-based systems in smart infrastructure, industrial monitoring, and consumer IoT applications.
The technical root cause of this vulnerability manifests as an out-of-bounds memory read condition classified under CWE-129, specifically representing an insufficient input validation flaw. When network packets arrive at a vulnerable RIOT device, they are cast into a sixlowpan_sfr_rfrag_t structure without first verifying that the incoming packet contains sufficient data to accommodate the entire structure. This improper memory management allows an attacker to craft malicious packets that, when processed by the 6LoWPAN stack, trigger unauthorized memory access patterns. The vulnerability operates at the network protocol level, where the system assumes all incoming packets conform to expected formats without proper bounds checking, creating a direct pathway for memory disclosure or system instability.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to complete system compromise or denial of service across deployed IoT infrastructure. An unauthenticated attacker with network access can potentially read adjacent memory locations, which may contain sensitive data such as cryptographic keys, authentication credentials, or system configuration parameters. The ability to crash vulnerable devices creates a significant availability risk, particularly in mission-critical applications where continuous operation is essential. This vulnerability affects devices operating in the 6LoWPAN protocol stack, which is commonly found in wireless sensor networks, smart grid devices, and various industrial IoT deployments, making the potential impact widespread across multiple sectors.
Mitigation strategies for this vulnerability require immediate attention from system administrators and device manufacturers. The primary recommendation involves implementing proper input validation checks before casting network packets into structured data types, ensuring that packet sizes are verified against expected structure dimensions. Organizations should consider updating to patched versions of RIOT OS as soon as they become available, though the current absence of a known patch requires immediate internal development of workarounds. Network segmentation and access control measures can provide temporary protection by limiting attacker access to vulnerable devices. Additionally, implementing intrusion detection systems capable of identifying malformed 6LoWPAN packets and monitoring for unusual memory access patterns can help detect exploitation attempts. This vulnerability aligns with ATT&CK technique T1059.007 for command and control through network protocols, and represents a significant risk to the security posture of IoT deployments relying on RIOT OS.