CVE-2023-33973: RIOT-OS vulnerable to NULL pointer dereference during NHC encoding

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-05-30 · updated 2026-06-17
Weakness: CWE-476

Description

RIOT-OS, an operating system for Internet of Things (IoT) devices, contains a network stack with the ability to process 6LoWPAN frames. In versions 2023.01 and prior, an attacker can send a crafted frame which is forwarded by the device. During encoding of the packet a NULL pointer dereference occurs. This crashes the device leading to denial of service. A patch is available at pull request 19678. There are no known workarounds.

Affected products

RIOT-OS RIOT: through 2023.01

References

https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1067
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1495
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1511
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1644
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1655
https://github.com/RIOT-OS/RIOT/commit/c9d7863e5664a169035038628029bb07e090c5ff
https://github.com/RIOT-OS/RIOT/pull/19678
https://github.com/RIOT-OS/RIOT/security/advisories/GHSA-r2pv-3jqc-vh7w
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1067
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1495
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1511
https://github.com/RIOT-OS/RIOT/blob/f41b4b67b6affca0a8b32edced7f51088696869a/sys/net/gnrc/network_layer/sixlowpan/iphc/gnrc_sixlowpan_iphc.c#L1644

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