Vulnerability in github.com/free5gc/smf (CVE-2026-44321)
Summary
Vulnerability in github.com/free5gc/smf (CVE-2026-44321). Risk of unauthorized operations or information disclosure. Exploitable via POST /upi/v1/upNodesLinks.
Original description
The description as published by the source.
Summary
free5GC's SMF mounts the UPI management route group without inbound OAuth2 middleware (same root cause as free5gc/free5gc#887). The POST /upi/v1/upNodesLinks create-or-update handler accepts attacker-controlled JSON and passes it directly into UpNodesFromConfiguration(), which calls logger.InitLog.Fatalf(...) on several validation failures. One confirmed path is the UE-IP-pool overlap check: a single unauthenticated POST that adds a new UPF whose pool overlaps an existing UPF terminates the entire SMF process (docker ps shows Exited (1)), not just the goroutine. This is a stronger sink than free5gc/free5gc#905: that one panics inside the request goroutine and Gin recovers; this one calls Fatalf which is os.Exit(1)-equivalent and kills the whole SMF process, dropping all of SMF's SBI surface (PDU-session establishment, UE policy lookups, etc.) until the process is restarted.
Details
Validated against the SMF container in the official Docker compose lab.
- Source repo tag:
v4.2.1 - Running Docker image:
free5gc/smf:v4.2.1 - Runtime SMF commit:
8385c00a - Docker validation date: 2026-03-22 local (container log timestamp
2026-03-21T23:47:07Z) - SMF endpoint:
http://10.100.200.6:8000
The broader UPI auth gap (#887) lets the unauthenticated POST reach the create/update handler. From there:
Vulnerable handler dispatches into topology parsing:
POST /upi/v1/upNodesLinks
-> UpNodesFromConfiguration()
-> isOverlap(allUEIPPools)…
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-2026-44321 has been found in github.com/free5gc/smf.
Attackers can target a specific entry point like POST /upi/v1/upNodesLinks over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "github.com/free5gc/smf CVE-2026-44321" on the vendor's site.
CVE-2026-44321 (github.com/free5gc/smf) — CWE-306 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /upi/v1/upNodesLinks / UPI / Fatalf / FATA
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.
A vulnerability (CWE-306) exists in github.com/free5gc/smf. Attackers reach the vulnerable code path via POST /upi/v1/upNodesLinks without authentication.
Check the vendor advisory for the affected versions of github.com/free5gc/smf. Attack surface: POST /upi/v1/upNodesLinks / UPI / Fatalf / FATA.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /upi/v1/upNodesLinks requests with malformed payloads or SQL meta-characters. Run grep -r 'github.com/free5gc/smf' . 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
-
1Identify exposure identify
grep -r 'github.com/free5gc/smf' . | 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/smfを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /upi/v1/upNodesLinks' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /upi/v1/upNodesLinks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。 -
3Post-deployment verification verify
Replay attack against POST /upi/v1/upNodesLinks 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
References
- advisory nvd.nist.gov
- exploit github.com
- exploit security-advisories@github.com
- package github.com
- patch security-advisories@github.com
- patch security-advisories@github.com
- web github.com