Security Vulnerabilities
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI management route group without OAuth2/bearer-token authorization middleware. A network attacker who can reach SMF on the SBI can hit UPI endpoints with no Authorization header at all, and the requests reach the SMF business handlers. In the running Docker lab this was directly demonstrated for read (GET /upi/v1/upNodesLinks), write (POST /upi/v1/upNodesLinks with attacker-controlled UP-node and link payload), and delete (DELETE /upi/v1/upNodesLinks/{nodeID}) operations. This vulnerability is fixed in 4.2.2.
CVSS Score
10.0
EPSS Score
0.001
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-pfdmanagement route group without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can use a forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) to read PFD application data via GET /applications and GET /applications/{appID}, and to create or delete PFD change-notification subscriptions via POST /subscriptions and DELETE /subscriptions/{subID}. Same root cause as the other NEF SBI findings: the route group is mounted without any inbound auth middleware. Unlike the OAM and traffic-influence groups, nnef-pfdmanagement IS declared in the runtime ServiceList, so this is the production-intended path that operators expect to be protected by OAuth2 setting receive from NRF: true -- and it is not. This vulnerability is fixed in 4.2.2.
CVSS Score
10.0
EPSS Score
0.0
Published
2026-05-27
Streamlink is a CLI utility which pipes video streams from various services into a video player. Prior to 8.4.0, Streamlink's HLS and DASH parsers do not validate the URI scheme of segment entries and other resources. A remote .m3u8 HLS playlist or .mpd DASH manifest can list file:///path/to/file as a segment, and streamlink will read that local file and write its contents to the output stream. This vulnerability is fixed in 8.4.0.
CVSS Score
6.5
EPSS Score
0.0
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF terminates the entire process when a stored PFD-subscription notifyUri cannot be reached. In PfdChangeNotifier.FlushNotifications(), the notifier calls NnefPFDmanagementNotify(...) and on any delivery error invokes logger.PFDManageLog.Fatal(err), which is os.Exit(1)-equivalent in Go. An attacker who can create a PFD subscription with an attacker-chosen notifyUri and then trigger a PFD change can deterministically kill NEF on the asynchronous delivery attempt -- the process exits with status 1, dropping NEF's entire SBI surface until restart. This vulnerability is fixed in 4.2.2.
CVSS Score
7.5
EPSS Score
0.001
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the nnef-callback route group without inbound OAuth2/bearer-token authorization. A forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) is enough to reach the SMF-callback handler -- the callback body is parsed and dispatched into NEF business logic instead of being rejected at the auth boundary. Same root cause as the other NEF SBI findings: the route group is mounted without any inbound auth middleware. NEF does not authenticate the producer NF identity before processing callback content; if an attacker can guess or obtain a valid NotifId, this missing auth boundary lets forged callbacks act on real subscription state. The route group is also reachable even when the runtime ServiceList does not declare it (it lists only nnef-pfdmanagement and nnef-oam). This vulnerability is fixed in 4.2.2.
CVSS Score
7.3
EPSS Score
0.0
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's SMF mounts the UPI management route group without inbound OAuth2 middleware. The POST /upi/v1/upNodesLinks create-or-update handler accepts attacker-controlled JSON and passes it directly into UpNodesFromConfiguration(), which calls logger.InitLog.Fatalf(...) on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (docker ps shows Exited (1)), not just the goroutine. This vulnerability is fixed in 4.2.2.
CVSS Score
7.5
EPSS Score
0.001
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF PATCH /3gpp-pfd-management/v1/{afId}/transactions/{transId}/applications/{appId} handler panics with a nil-pointer dereference when the upstream UDR call fails AND the consumer wrapper returns err != nil together with a nil *ProblemDetails. The handler's errPfdData != nil branch builds its own problemDetailsErr correctly, but immediately after it reads problemDetails.Cause (the OTHER value, which is nil in this branch) and panics. Gin recovery converts the panic into HTTP 500, so a single PATCH against this endpoint returns 500 instead of the intended controlled error response whenever UDR access is failing. This vulnerability is fixed in 4.2.2.
CVSS Score
7.5
EPSS Score
0.001
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's UDR nudr-dr DELETE /subscription-data/{ueId}/{servingPlmnId}/ee-subscriptions/{subsId}/amf-subscriptions handler contains a nil-pointer dereference reachable from a single authenticated request, after one preparatory authenticated EE-subscription create. The handler checks _, ok = UESubsData.EeSubscriptionCollection[subsId] and sets a 404 problem-details on the miss path, but then continues to UESubsData.EeSubscriptionCollection[subsId].AmfSubscriptionInfos -- dereferencing the same missing entry instead of returning. Gin recovery converts the panic into HTTP 500, but the endpoint remains repeatedly panicable. This vulnerability is fixed in 4.2.2.
CVSS Score
4.3
EPSS Score
0.001
Published
2026-05-27
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's UDR nudr-dr DELETE /subscription-data/{ueId}/{servingPlmnId}/ee-subscriptions/{subsId}/amf-subscriptions handler panics on a single authenticated request against a fresh UDR instance when the supplied ueId does not exist in UESubsCollection. The processor checks value, ok := udrSelf.UESubsCollection.Load(ueId) and sets a 404 USER_NOT_FOUND problem-details on the miss path, but execution continues and immediately runs value.(*udr_context.UESubsData) -- a Go type assertion on a nil interface, which panics with interface conversion: interface {} is nil, not *context.UESubsData. Gin recovery converts the panic into HTTP 500, but the endpoint remains repeatedly panicable. This vulnerability is fixed in 4.2.2.
CVSS Score
6.5
EPSS Score
0.001
Published
2026-05-27
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.
CVSS Score
7.5
EPSS Score
0.001
Published
2026-05-27