CVE-2026-44320 free5GC's NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path
Attackers can forge callback requests to the NEF component due to missing authentication, potentially modifying subscription state.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44320?
CVE-2026-44320 is a high-severity missing authorization vulnerability in Free5gc Free5gc, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, 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). This vulnerability is fixed in 4.2.2.
Which versions are affected by CVE-2026-44320?
3 open source packages ship an affected version, including github.com/free5gc/nef. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/free5gc/nef Go | All versions | None |
github.com/free5gc/nef Go | All versions to 1.2.3 | None |
github.com/free5gc/nef Go | All versions to 1.2.3 | None |
Products include Free5gc Free5gc.
How do I fix CVE-2026-44320?
Upgrade to a fixed version.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-44320 being exploited?
There is no known exploitation of CVE-2026-44320 in the wild and no public exploit code.
Other vulnerabilities in Free5gc Free5gc
- CVE-2026-44327 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
- CVE-2026-44329 free5GC's SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers
- CVE-2026-44330 free5GC's NEF nnef-pfdmanagement API is unauthenticated; forged bearer tokens can read PFD data and create/delete PFD subscriptions
- CVE-2025-63679 Memory corruption in n/a
- CVE-2026-44315 free5GC's NEF 3gpp-pfd-management API is unauthenticated; forged bearer tokens can create, read, and delete PFD transactions
Sources
Also known as GHSA-wqfh-gq79-j8mf, GO-2026-5717.