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CVE-2026-44318 medium CVSS 6.5

Vulnerability in github.com/free5gc/bsf (CVE-2026-44318)

Summary

Vulnerability in github.com/free5gc/bsf (CVE-2026-44318). Risk of unauthorized operations or information disclosure. Exploitable via PUT /nbsf-management/v1/subscriptions/{subId}. Mitigation: upgrade to 1.0.2 or later.

Original description

The description as published by the source.

Summary

free5GC's BSF PUT /nbsf-management/v1/subscriptions/{subId} handler has an unsynchronized write on the global Subscriptions map. The handler first reads the map under RLock() via BSFContext.GetSubscription(subId), but if the subscription does not exist, ReplaceIndividualSubcription() writes back to the same map directly without taking the mutex (bsfContext.BsfSelf.Subscriptions[subId] = subscription). Under concurrent authenticated PUT load, one goroutine can read while another writes the map, which causes the Go runtime to abort the process with fatal error: concurrent map read and map write (Go runtime panics that come from concurrent map access bypass recover() and terminate the process). The BSF container exits with code 2 -- the entire BSF SBI surface goes down until restart.

This endpoint requires a valid nbsf-management OAuth2 access token (PR:L, NOT PR:N), so this is scored as an authenticated process-kill DoS.

Details

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

  • Source repo tag: v4.2.1
  • Running Docker image: free5gc/bsf:v4.2.1
  • Docker validation date: 2026-03-22
  • BSF endpoint: http://10.100.200.11:8000

Read side (locked):

func (c *BSFContext) GetSubscription(subId string) (*BsfSubscription, bool) {
    c.mutex.RLock()
    defer c.mutex.RUnlock()

    sub, exists := c.Subscriptions[subId]
    return sub, exists
}

Unsafe write side in the create-if-absent branch of `ReplaceIndividua…

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-2026-44318 has been found in github.com/free5gc/bsf.
Attackers can target a specific entry point like PUT /nbsf-management/v1/subscriptions/{subId} over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade github.com/free5gc/bsf to 1.0.2 or later.
If unsure, ask your IT team or search "github.com/free5gc/bsf CVE-2026-44318" on the vendor's site.

CVE-2026-44318 (github.com/free5gc/bsf) — CWE-362 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: PUT /nbsf-management/v1/subscriptions/{subId} / Subscriptions / ReplaceIndividualSubcription / c.Subscriptions
Patched: 1.0.2 — 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-362) exists in github.com/free5gc/bsf. Attackers reach the vulnerable code path via PUT /nbsf-management/v1/subscriptions/{subId}.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/free5gc/bsf. Attack surface: PUT /nbsf-management/v1/subscriptions/{subId} / Subscriptions / ReplaceIndividualSubcription / c.Subscriptions.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.0.2.

🛡️ 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 PUT /nbsf-management/v1/subscriptions/{subId} requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/free5gc/bsf' . 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/bsf' . | 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/bsf 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 'PUT /nbsf-management/v1/subscriptions/{subId}' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで PUT /nbsf-management/v1/subscriptions/{subId} 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/bsf to 1.0.2

    ステージング環境で 1.0.2 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 PUT /nbsf-management/v1/subscriptions/{subId} 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/bsf
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.2"}]}]

References

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