CVE-2025-66646

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:riot-os:riot:*:*:*:*:*:*:*:*
cpe:2.3:o:riot-os:riot:2025.10:rc1:*:*:*:*:*:*
cpe:2.3:o:riot-os:riot:2025.10:rc2:*:*:*:*:*:*
cpe:2.3:o:riot-os:riot:2025.10:rc3:*:*:*:*:*:*

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 - () 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 - () 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 - () 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 - () 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 - () 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 - () 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 - () 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 - () 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 - () 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 - () https://github.com/user-attachments/files/23903992/reproducer_1.zip - Exploit
First Time Riot-os
Riot-os riot
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:*:*:*:*:*:*
CVSS v2 : unknown
v3 : unknown
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