An integer truncation vulnerability in the NAS decoder of OpenAirInterface (OAI) CN5G AMF v2.2.1 allows an unauthenticated remote attacker to cause a denial of service (DoS) via crafted NAS Registration Requests containing a malformed IMEISV in the 5GS Mobile Identity IE. The Type6NasIe::Validate() function truncates a 32-bit length value to 16 bits, bypassing length validation and causing an out-of-bounds heap read in DecodeImeisv(), which can crash the AMF process.
https://github.com/openairinterface/oai-cn5g-amf/issues/16
https://gist.github.com/hackeryounow/1c6741be7d536bd98434ac270dbb1f60