# CVE-2026-30067: free5gc NRF Discovery denial of service in complexQueryFilterSubprocess

Source: https://junglewise.ai/threats/cve-2026-30067-free5gc-nrf-discovery-denial-of-service-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-27. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-30067 · Severity: high · CVSS 7.5 · Published 2026-08-27

free5gc is an open-source 5G core network implementation that provides services for network device discovery. The NRF Discovery service contains a flaw in input validation that allows an attacker to crash the service with a specially crafted request, disrupting network operations and availability of critical 5G infrastructure components.

Technologies: [free5GC](https://junglewise.ai/threats/technologies/free5gc). Vendors: [free5GC](https://junglewise.ai/threats/vendors/free5gc).

## Quick answers

**Is CVE-2026-30067 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-30067 being exploited in the wild.

**How severe is CVE-2026-30067?** High severity, with a CVSS score of 7.5, published 27 August 2026.

**Which products and versions are affected?** free5GC v4.0.1.

**Is there a fix for CVE-2026-30067?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-30067 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-30067?** Check whether you run free5GC at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the complexQueryFilterSubprocess function within the NRF Discovery service (nf_discovery.go:1556). The code splits the "tai" parameter by commas and directly accesses array indices [0] and [1] without validating that the split operation produces at least two elements. When a malformed tai parameter is provided (e.g., containing fewer than two comma-separated values), accessing taiSplit[1] triggers an index out of range panic, causing the handler to crash. This is a classic input validation flaw affecting a network-reachable API endpoint; no authentication is required. The attack can be exploited remotely by sending a specially crafted GET request to the NF discovery endpoint with a malformed complexQuery parameter, causing denial of service.

## Affected products

- free5gc free5gc v4.0.1

## Timeline

- 2026-01-06: disclosed
- 2026-08-27: advisory

## References

- [https://github.com/free5gc/free5gc/issues/771](https://github.com/free5gc/free5gc/issues/771)

## Related threats

- [Free5GC SMF resource exhaustion in PFCP session establishment](https://junglewise.ai/threats/cve-2026-106805-a-resource-exhaustion-issue-exists-in-free5gc-v4-2-3-during-pfcp)
- [Free5GC race condition in GMM handler RanUe context access](https://junglewise.ai/threats/cve-2026-94043-a-vulnerability-was-determined-in-free5gc-up-to-4-2-3-this)
- [Free5GC UPF nil pointer dereference in PFCP Session Report](https://junglewise.ai/threats/cve-2026-75439-free5gc-upf-nil-pointer-dereference-in-pfcp-session-report)
- [free5GC NRF input validation bypass in NF profile registration](https://junglewise.ai/threats/cve-2026-55068-free5gc-nrf-input-validation-bypass-in-nf-profile-registration)
- [free5gc NSSF nil pointer dereference in NssaiAvailabilitySubscriptionCreate](https://junglewise.ai/threats/cve-2026-30073-free5gc-nssf-nil-pointer-dereference-in)