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CVE-2026-44327 critical CVSS 10.0

Vulnerability in github.com/free5gc/nef (CVE-2026-44327)

Summary

Vulnerability in github.com/free5gc/nef (CVE-2026-44327). Data can be tampered with by attackers. Exploitable via Authorization.

Original description

The description as published by the source.

Summary

free5GC's NEF mounts the nnef-oam route group without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can hit the OAM route with no Authorization header at all and the handler returns 200 OK. The current OAM handler is a stub that returns null, but the structural defect is route-group-scoped: the entire OAM route group has no inbound auth middleware, so every future OAM operation added to this group inherits the missing auth boundary by default. Same root cause as the NEF traffic-influence and PFD-management findings.

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, yet the OAM route group is mounted without any inbound auth middleware and answers unauthenticated GETs with 200 OK.

Code evidence (paths in free5gc/nef):

  • OAM route group mounted without auth middleware: NFs/nef/internal/sbi/server.go:60
  • OAM route exposed at /: NFs/nef/internal/sbi/api_oam.go:9
  • OAM processor returns 200 OK directly: NFs/nef/internal/sbi/processor/oam.go:9
  • NEF context only exposes outbound token acquisition (GetTokenCtx); there is no inbound authorization path: NFs/nef/internal/context/nef_context.go:153

PoC

Reproduced against the running NEF at `http://10.100.200.19:8000…

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-2026-44327 has been found in github.com/free5gc/nef.
Attackers can target a specific entry point like Authorization over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 10.0/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "github.com/free5gc/nef CVE-2026-44327" on the vendor's site.

CVE-2026-44327 (github.com/free5gc/nef) — CWE-306 / CVSS v3 10.0
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Authorization / null / GET / GetTokenCtx
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-306) exists in github.com/free5gc/nef. Attackers reach the vulnerable code path via Authorization without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/free5gc/nef. Attack surface: Authorization / null / GET / GetTokenCtx.

🔥 Severity

Severity: Critical (CVSS 10.0/10). Data can be tampered with by attackers.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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 request patterns matching this CVE's known IOCs. Run grep -r 'github.com/free5gc/nef' . 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/nef' . | 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/nef 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
    Post-deployment verification verify 
    Confirm patched version is live in production

    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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go github.com/free5gc/nef
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"1.2.3"}]}]

References

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