RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. A vulnerability was discovered in the IPv6 fragmentation reassembly implementation of RIOT OS v2025.07. When receiving an fragmented IPv6 packet with fragment offset 0 and an empty payload, the payload pointer is set to NULL. However, the implementation still tries to copy the payload into the reassembly buffer, resulting in a NULL pointer dereference which crashes the OS (DoS). To trigger the vulnerability, the `gnrc_ipv6_ext_frag` module must be enabled and the attacker must be able to send arbitrary IPv6 packets to the victim. RIOT OS v2025.10 fixes the issue.
References
Configurations
Configuration 1 (hide)
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History
22 Jan 2026, 16:22
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L411 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L420 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L490 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L532 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L534 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L544 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/pktbuf_static/gnrc_pktbuf_static.c#L150C1-L150C76 - Product | |
| References | () https://github.com/RIOT-OS/RIOT/releases/tag/2025.10 - Release Notes | |
| References | () https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-v8gx-q9m6-5xm9 - Exploit, Vendor Advisory, Patch | |
| References | () https://github.com/user-attachments/files/23903992/reproducer_1.zip - Exploit | |
| First Time |
Riot-os
Riot-os riot |
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| CPE | cpe:2.3:o:riot-os:riot:2025.10:rc2:*:*:*:*:*:* cpe:2.3:o:riot-os:riot:2025.10:rc3:*:*:*:*:*:* cpe:2.3:o:riot-os:riot:*:*:*:*:*:*:*:* cpe:2.3:o:riot-os:riot:2025.10:rc1:*:*:*:*:*:* |
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| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.5 |
17 Dec 2025, 20:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-12-17 20:15
Updated : 2026-01-22 16:22
NVD link : CVE-2025-66646
Mitre link : CVE-2025-66646
CVE.ORG link : CVE-2025-66646
JSON object : View
Products Affected
riot-os
- riot
CWE
CWE-476
NULL Pointer Dereference
