# CVE-2026-30057: free5gc AMF CreateUEContext denial of service via multipart deserialization

Source: https://junglewise.ai/threats/cve-2026-30057-free5gc-amf-createuecontext-denial-of-service-via-multipart  
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-2026-30057 · Severity: high · CVSS 7.5 · Published 2026-08-27

free5gc's Access and Mobility Management Function (AMF) is a core component of 5G networks responsible for managing device connections and authentication. A flaw in how it handles certain types of HTTP requests allows an unauthenticated attacker to crash the AMF service by sending a specially crafted request, causing a complete denial of service to all connected users on that network element.

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

## Quick answers

**Is CVE-2026-30057 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-30057 being exploited in the wild.

**How severe is CVE-2026-30057?** High severity, with a CVSS score of 7.5, published 27 August 2026.

**Which products and versions are affected?** free5GC v4.1.0.

**Is there a fix for CVE-2026-30057?** 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-2026-30057 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-30057?** 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 is an unhandled panic in the CreateUEContext handler (HTTPCreateUEContext in api_communication.go) when processing requests with Content-Type: multipart/related. The root cause is improper deserialization in the openapi.MultipartDeserialize function, which attempts an illegal reflection operation (FieldByName on a slice type) when parsing the multipart payload. This causes an unrecoverable panic that crashes the AMF process. The attack requires no authentication and is network-reachable at the SBI endpoint, allowing any attacker with network access to the AMF to trigger a denial of service. A patch addressing the improper deserialization logic is needed to either correctly handle multipart/related content or reject it gracefully.

## Affected products

- free5gc free5gc v4.1.0

## Timeline

- 2026-01-01: disclosed: Issue reported on GitHub #755
- 2026-08-27: advisory: CVE-2026-30057 published

## References

- [https://github.com/free5gc/free5gc/issues/755](https://github.com/free5gc/free5gc/issues/755)

## Related threats

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- [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)