A resource exhaustion issue exists in Free5GC v4.2.3 during PFCP Session Establishment failure handling. When the SMF does not receive a PFCP Session Establishment Response from the UPF, allocated UE IP address resources are not properly released. Repeated failed session establishment attempts can therefore exhaust the UE IP address pool, preventing new UEs from establishing PDU sessions and resulting in denial of service.

free5GC AMF missing default case in Content-Type switch in HTTPUEContextTransfer

free5GC AMF provides Access & Mobility Management Function (AMF) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. Prior to version 1.4.3, the `HTTPUEContextTransfer` handler in `internal/sbi/api_communication.go` does not include a `default` case in the `Content-Type` switch statement. When a request arrives with an unsupported `Content-Type`, the deserialization step is silently skipped, `err` remains `nil`, and the processor is invoked with a completely uninitialized `UeContextTransferRequest` object. Version 1.4.3 contains a fix.

free5gc UDR improper path validation allows unauthenticated deletion of Traffic Influence Subscriptions

free5GC is an open-source implementation of the 5G core network. In versions 1.4.2 and below of the UDR service, the handler for deleting Traffic Influence Subscriptions checks whether the influenceId path segment equals subs-to-notify, but does not return after sending the HTTP 404 response when validation fails. Execution continues and the subscription is deleted regardless. An unauthenticated attacker with access to the 5G Service Based Interface can delete arbitrary Traffic Influence Subscriptions by supplying any value for the influenceId path segment, while the API misleadingly returns a 404 Not Found response. A patched version was not available at the time of publication.

Free5GC Gmm handler.go race condition

A vulnerability was determined in Free5GC up to 4.2.3. This vulnerability affects unknown code of the file /corefuzzer_deps/free5gc/NFs/amf/internal/gmm/handler.go of the component Gmm Handler. This manipulation causes race condition. The attack can be initiated remotely. Patch name: e323b01464355781b8b8d5dd695e05cbc00a62f2. To fix this issue, it is recommended to deploy a patch.

free5GC: UDR Improper ueId validation in free5GC EE subscription handlers allows arbitrary identifier persistence

free5GC is an open-source implementation of the 5G core network. In 4.2.3 and earlier, HandleCreateEeSubscriptions and HandleQueryeesubscriptions in free5gc/udr internal/sbi/api_datarepository.go validate the ueId path value with a regular expression whose final .+ alternative accepts every non-empty string instead of restricting identifiers to supported SUPI and GPSI formats. An actor with network reachability to the UDR SBI can submit a non-3GPP identifier to /nudr-dr/v2/subscription-data/{ueId}/context-data/ee-subscriptions, causing the identifier to pass validation and enter the normal create or query flow. The advisory does not independently establish whether authentication is required. Invalid identifiers can be persisted and retrieved as subscription records, enabling unauthorized data creation, UDR namespace pollution, persistent subscriber-metadata corruption, and interference with downstream components that trust stored identifiers to use valid 3GPP formats. The exposure is most relevant in lab, test, or loosely segmented service-based-interface deployments where direct UDR access is possible.

free5GC: NRF nnrf-nfm lacks NF Profile input validation — enables NF Registration Poisoning with arbitrary service endpoints

free5GC is an open-source implementation of the 5G core network. In 4.2.2 and earlier, the NRF RegisterNFInstance handler at PUT /nnrf-nfm/v1/nf-instances/{nfInstanceID} accepts NF Profiles without enforcing UUID format, nfStatus enum values, heartBeatTimer ranges, mandatory profile fields, or nfServices.ipEndPoints address constraints. The invalid profiles are persisted in the MongoDB NfProfile collection and returned by NFDiscover, allowing an attacker with SBI access to advertise attacker-controlled network-function endpoints and redirect control-plane signaling. This can expose credentials and signaling, alter service discovery integrity, and deny service across network functions that trust the NRF. This issue is fixed in version 4.2.3.

Free5GC NssaiAvailabilitySubscriptionCreate Component Denial of Service via Crafted POST

An issue in the NssaiAvailabilitySubscriptionCreate component of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted POST request.

free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI

free5GC is an open-source implementation of the 5G core network. In version 1.4.4 and earlier, the AUSF component stores per-subscriber authentication state in a global sync.Map named AUSFContext.UePool in internal/context/context.go, keyed only by SUPI. Every request handled by internal/sbi/processor/ue_authentication.go creates an AusfUeContext, and AddAusfUeContextToPool executes ausfContext.UePool.Store(ausfUeContext.Supi, ausfUeContext), unconditionally replacing the active context for that SUPI. An attacker with access to the AUSF SBI/N12 interface can send concurrent POST /nausf-auth/v1/ue-authentications requests for the same target SUPI, causing all attempts to share one logical authentication context URL while K_aut, XRES, and EapID are repeatedly overwritten. A valid EAP-AKA' response for an earlier challenge is then checked against the latest context, causing AT_MAC verification to fail and denying authentication to the selected subscriber while the request flood continues. No fixed version is available as of this review.

Denial of Service via Malformed SUCI Data in free5gc v4.0.1

An issue in free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) when parsing crafted SUCI data during UE registration.

Free5GC NF Discovery Denial of Service Vulnerability

An issue in the NF Discovery endpoint of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted snssais query.

Denial of Service via HandleGetSharedData in free5gc v4.0.1

An issue in the HandleGetSharedData function of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted input.

An issue in the ModifyAMFEventSubscriptionProcedure function (processor/event_exposure.go) of free5gc v4.1.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted PATCH request.

An issue in the CreateUEContext handler component of free5gc v4.1.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted request.

A NULL pointer dereference in the AMF NGAP Dispatcher component of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via supplying crafted NGAP messages during the initialization of a new RAN connection.

An issue in the complexQueryFilterSubprocess function in the NRF Discovery service of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted input.

An issue in the CreateUEContextProcedure function (/v1/ue-contexts/{supi}) of free5gc v4.1.0 allows attackers to cause a Denial of Service (DoS) via supplying a crafted PUT request.

An issue in the NAS decoder component of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted Registration Request message.

free5GC AUSF uses non-constant-time authentication comparisons and logs XRES* in 5G-AKA

free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the AUSF component performs cryptographic authentication comparisons in internal/sbi/processor/ue_authentication.go with ordinary equality helpers. Auth5gAkaComfirmRequestProcedure compares RES* and XRES* with strings.EqualFold and logs the expected XRES* value at INFO level before comparison. EapAuthComfirmRequestProcedure compares AT_MAC and XMAC with bytes.Equal and evaluates XRES == RES with ordinary string equality. These comparisons can return at mismatch-dependent times, although testing did not demonstrate a practical remote timing oracle because of HTTP/SBI timing noise. The INFO log exposes authentication material to operators, log collectors, sidecars, or processes able to read AUSF logs. This issue is fixed in version 1.4.5.

Improper Input Validation in the HTTPModifySubscription handler of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted input.

Improper input validation in the buildFilter function (processor/processor.go) of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted input.