Categories
CVE-2026-44325 high CVSS 7.5

Vulnerability in github.com/free5gc/nrf (CVE-2026-44325)

Summary

Vulnerability in github.com/free5gc/nrf (CVE-2026-44325). Risk of unauthorized operations or information disclosure. Exploitable via POST /oauth2/token. Mitigation: upgrade to 1.4.3 or later.

Original description

The description as published by the source.

Summary

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 across at least 6 confirmed crashing fields.

Note: /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.

Details

Validated against the NRF container in the official Docker compose lab.

  • Source repo tag: v4.2.1
  • Running Docker image: free5gc/nrf:v4.2.1
  • Docker validation date: 2026-03-22
  • NRF endpoint: http://10.100.200.3:8000

Root cause is in the access-token request parser:

  • NFs/nrf/internal/sbi/api_accesstoken.go:52
  • NFs/nrf/internal/sbi/api_accesstoken.go:87
  • NFs/nrf/internal/sbi/api_accesstoken.go:98
  • `NFs/nrf/internal/sbi/api_…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-44325 has been found in github.com/free5gc/nrf.
Attackers can target a specific entry point like POST /oauth2/token over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade github.com/free5gc/nrf to 1.4.3 or later.
If unsure, ask your IT team or search "github.com/free5gc/nrf CVE-2026-44325" on the vendor's site.

CVE-2026-44325 (github.com/free5gc/nrf) — CWE-20 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /oauth2/token / models.NrfAccessTokenAccessTokenReq / string / NrfNfManagementNfType
Patched: 1.4.3 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-20) exists in github.com/free5gc/nrf. Attackers reach the vulnerable code path via POST /oauth2/token without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/free5gc/nrf. Attack surface: POST /oauth2/token / models.NrfAccessTokenAccessTokenReq / string / NrfNfManagementNfType.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.4.3.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual POST /oauth2/token requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/free5gc/nrf' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    grep -r 'github.com/free5gc/nrf' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/free5gc/nrf を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect
    grep 'POST /oauth2/token' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /oauth2/token への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。

  3. 3
    Apply patch patch
    Upgrade github.com/free5gc/nrf to 1.4.3

    ステージング環境で 1.4.3 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。

  4. 4
    Post-deployment verification verify
    Replay attack against POST /oauth2/token on staging to confirm patch closes the vector

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

go github.com/free5gc/nrf
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.4.3"}]}]

References

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