NULL pointer dereference in Free5gc
CVE-2026-44323
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's UDR nudr-dr DELETE /subscription-data/{ueId}/{servingPlmnId}/ee-subscriptions/{subsId}/amf-subscriptions handler contains a nil-pointer dereference reachable from a single authenticated request, after one preparatory authenticated EE-subscription create. The handler checks _, ok = UESubsData.EeSubscriptionCollection[subsId] and sets a 404 problem-details on the miss path, but then continues to UESubsData.EeSubscriptionCollection[subsId].AmfSubscriptionInfos -- dereferencing the same missing entry instead of returning. Gin recovery converts the panic into HTTP 500, but the endpoint remains repeatedly panicable. This vulnerability is fixed in 4.2.2.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.006 (45.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 45.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Free5gc — versions < 4.2.2
Weakness classification (CWE)
References
- github.com/free5gc/free5gc/security/advisories/GHSA-4rqf-grm6-vf75 (Exploit, Vendor Advisory)
- github.com/free5gc/free5gc/issues/919 (Exploit, Issue Tracking)
- github.com/free5gc/udr/pull/60 (Patch, Issue Tracking)
- github.com/free5gc/udr/commit/8a1d3c63be99d378806d771f086ff32f1867da99 (Patch)
Frequently asked questions
- What is CVE-2026-44323?
- CVE-2026-44323 is a medium-severity vulnerability in Free5gc, classified under NULL Pointer Dereference. CVSS score: 4.3/10. Published 2026-05-27.
- How severe is CVE-2026-44323?
- Medium severity. CVSS v3 base score is 4.3 out of 10.