CVE-2026-44325
HighSummary
In versions prior to 4.2.2, free5GC contains a type confusion bug in the POST /oauth2/token endpoint that can lead to server panic. This bug arises from improper handling of fields in the request, allowing an attacker to trigger server panic through a specially crafted request.
Risk Assessment
The organization may be exposed to attacks that lead to server crashes, resulting in service availability interruptions. Additionally, the ability to remotely trigger server panic from an unauthenticated request increases the risk of potential attacks.
Recommendation
It is recommended to upgrade to version 4.2.2 or later to mitigate this vulnerability. Additionally, monitoring server logs for potential exploitation attempts is advisable.
Original NVD description (English source)
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 HTTP 500, but the endpoint remains remotely panicable from a single unauthenticated form-encoded request and is repeatedly triggerable. This vulnerability is fixed in 4.2.2.