free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS

• CVE-2026-44320: 0.24% estimated exploitation activity in the next 30 days; percentile 15.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary free5GC's NEF mounts the nnef-callback route group without inbound OAuth2/bearer-token authorization. A forged or arbitrary bearer token (e.g. Authorization: Bearer not-a-real-token) is enough to reach the SMF-callback handler -- the callback body is parsed and dispatched into NEF business logic instead of being rejected at the auth boundary. Same root cause as the other NEF SBI findings: the route group is mounted without any inbound auth middleware. NEF does not authenticate the producer NF identity before processing callback content; if an attacker can guess or obtain a valid NotifId, this missing auth boundary lets forged callbacks act on real subscription state. The route group is also reachable even when the runtime ServiceList does not declare it (it lists only nnef-pfdmanagement and nnef-oam). Details Validated against the NEF container in the official Docker compose lab. - Running Docker image: free5gc/nef:v4.2.1 - Docker validation date: 2026-03-11 NEF advertises…

Published by the source

8 May 2026, 22:46 UTC

Last modified by the source

8 Jun 2026, 23:47 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wqfh-gq79-j8mf

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# Patch Next advisory brief: CVE-2026-44320

Advisory: free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path
IDs: CVE-2026-44320, GHSA-wqfh-gq79-j8mf
Record: https://patchnext.com/advisories/cve-2026-44320 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/nef: affected <= 1.2.3

## Suggested inspection (read-only)
- Go github.com/free5gc/nef: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/nef.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wqfh-gq79-j8mf (GitHub-reviewed advisory GHSA-wqfh-gq79-j8mf lists affected ranges: Go github.com/free5gc/nef >=0 <=1.2.3)

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