Open5GS v2.7.5, prior to commit 67ba7f92bbd7a378954895d96d9d7b05d5b64615, is vulnerable to a NULL pointer dereference when a multipart/related HTTP POST request with an empty HTTP body is sent to the SBI of either AMF, AUSF, BSF, NRF, NSSF, PCF, SMF, UDM, or UDR, resulting in a denial of service. This occurs in the parse_multipart function in lib/sbi/message.c.
The product dereferences a pointer that it expects to be valid but is NULL.