Auth bypass in Free5gc
CVE-2026-44326
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF mounts the 3gpp-traffic-influence API without inbound OAuth2/bearer-token authorization. A network attacker who can reach NEF on the SBI can create, read, patch, and delete traffic-influence subscriptions either with no Authorization header at all, or with a forged bearer token (e.g. Authorization: Bearer not-a-real-token). This includes creating AnyUeInd=true subscriptions intended to affect group / any-UE traffic steering. The route group is also reachable even when the running config's ServiceList does not declare it, so operators who think they disabled the service via config are still exposed. This vulnerability is fixed in 4.2.2.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (42.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Free5gc — versions < 4.2.2
Weakness classification (CWE)
References
- github.com/free5gc/free5gc/security/advisories/GHSA-3p28-73q7-45xp (Exploit, Vendor Advisory)
- github.com/free5gc/free5gc/issues/859 (Exploit, Issue Tracking)
- github.com/free5gc/nef/pull/23 (Patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-44326?
- CVE-2026-44326 is a critical-severity vulnerability in Free5gc, classified under Missing Authorization. CVSS score: 9.4/10. Published 2026-05-27.
- How severe is CVE-2026-44326?
- Critical severity. CVSS v3 base score is 9.4 out of 10.