CVE-2026-44327 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler
Attackers can access unauthenticated NEF OAM routes in free5GC, bypassing authorization controls on the Service Based Interface.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44327?
CVE-2026-44327 is a critical 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-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.
Which versions are affected by CVE-2026-44327?
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-2026-44327?
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-2026-44327 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44327 exists.
Other vulnerabilities in Free5gc Free5gc
- 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
- CVE-2026-44326 free5GC's NEF 3gpp-traffic-influence API is unauthenticated; missing or forged bearer tokens can create, read, patch, and delete subscriptions
Sources
Also known as GHSA-cmpj-2x3g-m7g3, GO-2026-5326.