Vulnerability · Published May 27, 2026 · Assigned by GitHub_M
CVE-2026-44320free5GC: NEF nnef-callback route group is unauthenticated; forged callback requests are accepted into the processing path
High 7.3
In plain English
A high-severity missing authentication in free5gc from free5gc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/free5gc/nef | no fix listed | GHSA-wqfh-gq79-j8mf |
| Go | github.com/free5gc/nef | no fix listed | GO-2026-5717 |
Affected products (as reported)
Weakness: CWE-306, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
References
- https://github.com/free5gc/free5gc/security/advisories/GHSA-wqfh-gq79-j8mf x_refsource_CONFIRM
- https://github.com/free5gc/free5gc/issues/860 x_refsource_MISC
- https://github.com/free5gc/nef/pull/24 x_refsource_MISC