RIOT-OS has NULL pointer dereference in gnrc_ipv6_ext_frag_reass

Summary

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.

Timeline

1. Dec 17, 2025, 7:18 PM UTCCVE published
2. Dec 17, 2025, 8:26 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Dec 17, 2025, 8:30 PM UTCRecord last updated

Affected versions

• RIOT-OS RIOT

  fixed in 2025.10

References 10