CVE-2026-44327
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedfree5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, 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. This vulnerability is fixed in 4.2.2.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceIn free5GC versions prior to 4.2.2, the NEF (Network Exposure Function) mounts the nnef-oam route group without any inbound OAuth2/bearer-token authorization middleware. A network attacker who can reach the NEF on the SBI can access OAM endpoints without providing any Authorization header, receiving 200 OK responses. This is a route-group-scoped structural defect where the entire OAM route group lacks authentication, causing any future OAM operations added to this group to inherit the missing auth boundary.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 4.2.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify free5GC versionLocate the installed free5GC version by checking the package manager, container image tag, or binary version information. Common methods: 'free5gc --version', checking docker images, or reviewing installation manifests.Affected if Version is below 4.2.2 (e.g., 4.2.1, 4.2.0, earlier releases)
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Confirm NEF component is deployedIdentify whether the Network Exposure Function (NEF) component is running in your free5GC deployment. Check active processes, container/pod status, or service orchestration configuration for the 'nef' service.Affected if NEF component is deployed and running
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Locate NEF configuration filesFind the NEF configuration files in your free5GC deployment. Common locations include /free5gc/config/, /etc/free5gc/, or mounted config volumes in containerized deployments. Look for files named 'nefcfg.yaml', 'nef.conf', or similar.Affected if NEF configuration files exist and are accessible for inspection
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Inspect OAM route group configurationExamine the NEF configuration for the nnef-oam route group definition. Check for route group registration, endpoint definitions, and middleware chaining. Look for sections defining OAM API routes and their middleware stack.Affected if The nnef-oam route group is defined without oauth2, bearer-token, or authorization middleware in its middleware chain
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Test OAM endpoint accessibilitySend an HTTP request to a known NEF OAM endpoint (such as /nnef-oam/ or health/status endpoints) without including any Authorization header or bearer token. Observe the HTTP response status code.Affected if Request returns 200 OK without providing any Authorization header, indicating missing authentication enforcement
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Verify authentication middleware presenceReview the source code or configuration of the NEF service to confirm whether OAuth2 or bearer-token validation middleware is explicitly applied to the OAM route group endpoints.Affected if No authentication middleware is bound to the OAM route group
If free5GC version is prior to 4.2.2 AND the NEF OAM endpoints respond with 200 OK when accessed without an Authorization header, then the environment is affected by CVE-2026-44327.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped4.2.2
Upgrade free5GC to version 4.2.2 or later, which implements proper OAuth2/bearer-token authorization middleware on the OAM route group.
free5GC 4.2.2
- Identify current free5GC version running in the environment
- Plan maintenance window for upgrade
- Backup current free5GC configuration and data
- Upgrade free5GC to version 4.2.2 or later
- Verify the NEF component starts successfully
- Test that the NEF OAM routes now require proper authentication
- Confirm the upgrade did not introduce regressions in other services
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-44327 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-44327 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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