{"id":"CVE-2025-66646","summary":"RIOT-OS has NULL pointer dereference in gnrc_ipv6_ext_frag_reass","details":"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.","aliases":["GHSA-v8gx-q9m6-5xm9"],"modified":"2026-08-12T03:51:17.096426762Z","published":"2025-12-17T19:18:08.696Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66646.json"},"references":[{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L411"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L420"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L490"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L532"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L534"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/network_layer/ipv6/ext/frag/gnrc_ipv6_ext_frag.c#L544"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/blob/eb65305cf9f1b7affb50b17af5c12341b83a8636/sys/net/gnrc/pktbuf_static/gnrc_pktbuf_static.c#L150C1-L150C76"},{"type":"WEB","url":"https://github.com/RIOT-OS/RIOT/releases/tag/2025.10"},{"type":"WEB","url":"https://github.com/user-attachments/files/23903992/reproducer_1.zip"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66646.json"},{"type":"ADVISORY","url":"https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-v8gx-q9m6-5xm9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-66646"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/riot-os/riot","events":[{"introduced":"0"},{"fixed":"d271fc88a4edbaaaea097717aa1f118700cdbb63"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2025.10"}],"source":"AFFECTED_FIELD"}}],"versions":["2025.07-devel","2025.04-RC1","2025.04-devel","2025.01-RC1","2025.01-devel","2024.10-RC1","2024.10-devel","2024.07-RC1","2024.04","2024.07-devel","2024.04-RC1","2024.04-devel","2024.01-RC1","2024.01-devel","2023.10-RC1","2023.10-devel","2023.07-RC1","2023.07-devel","2023.04-RC1","2023.04-devel","2023.01-RC1","2023.01-devel","2022.10-RC1","2022.10-devel","2022.07-RC1","2022.07-devel","2022.04-RC1","2022.04-devel","2022.01-RC1","2022.01-devel","2021.10-RC1","2021.10-devel","2021.07-RC1","2021.07-devel","2021.04-RC1","2021.04-devel","2021.01-RC1","2021.01-devel","2020.10-RC1","2020.10-devel","2020.07-RC1","2020.07-devel","2020.04-RC1","2020.04-devel","2020.01-RC1","2020.01-devel","2019.10-RC1","2019.10-devel","2019.07-RC1","2019.07-devel","2019.04-RC1","2019.04-devel","2019.01-RC1","2018.10-devel","2018.07-RC1","2019.01-devel","2018.10-RC1","2018.07-devel","2018.04-RC1","2018.04-devel","2018.01-RC1","2018.01-devel","2017.10-RC1","2017.10-devel","2017.07-RC1","2017.07-devel","2017.04-RC1","2017.04-devel","2017.01-RC1","2017.01-devel","2016.10-RC1","2016.10-devel","2016.07-RC2","2016.07-RC1","2016.04-RC1","2016.07-devel","2016.03-devel","2015.12-RC1","2015.12-devel","2015.09-RC1","2014.12","2014.05","2014.01","2013.08"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-66646.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U"}]}