CVE-2026-53551

free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the free5GC AUSF (Authentication Server Function) does not validate the supiOrSuci field in UE authentication requests. Null bytes (\x00) and other control characters pass through JSON parsing unchanged and are forwarded to the UDM in an unescaped URL path. This causes Go's net/url.Parse() to fail, returning HTTP 500 "System failure" and leaking internal stack traces. An unauthenticated attacker can trigger this at scale causing denial of service for all subscribers attempting authentication through the affected AUSF. This vulnerability is fixed in 1.4.5.

CVSS

No CVSS.

References

Link	Resource
https://github.com/free5gc/ausf/commit/bfc4a10094dbacbd862baa4686829f3fcc06ce1e
https://github.com/free5gc/ausf/pull/61
https://github.com/free5gc/ausf/releases/tag/v1.4.5
https://github.com/free5gc/free5gc/issues/1048
https://github.com/free5gc/free5gc/releases/tag/v4.2.2
https://github.com/free5gc/free5gc/security/advisories/GHSA-qj55-47fp-p62j
https://github.com/free5gc/free5gc/security/advisories/GHSA-qj55-47fp-p62j

Configurations

No configuration.

History

No history.

Information

Published : 2026-07-31 20:16

Updated : 2026-09-08 20:51

NVD link : CVE-2026-53551

Mitre link : CVE-2026-53551

CVE.ORG link : CVE-2026-53551

JSON object : View

Products Affected

No product.

CWE

CWE-20

Improper Input Validation

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