CVSS7.5
Severityhigh
WeaknessCWE-20
ExploitedNot in CISA KEV
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NRF root SBI endpoint POST /oauth2/token contains a parser-level type-confusion bug family. The handler in NFs/nrf/internal/sbi/api_accesstoken.go reflects over models.NrfAccessTokenAccessTokenReq, special-cases only plain string and NrfNfManagementNfType fields, and treats every other field as if it were a single models.PlmnId. The parsed *models.PlmnId is then assigned with reflect.Value.Set() to whichever field name the attacker put in the form body, which panics whenever the destination field's real type is incompatible (slice, different struct, primitive). Gin recovery converts each panic into HTT