CVE-2026-53551
MediumCVSS 6.9Exploitation Probability (EPSS)
Low risk35th percentile - higher than 35% of all known CVEs
Summary
In free5GC prior to version 1.4.5, the AUSF does not validate the supiOrSuci field in UE authentication requests. Null bytes and other control characters pass through JSON parsing and are forwarded to the UDM in an unescaped URL path, causing Go's net/url.Parse() to fail and return HTTP 500 with stack trace leakage. An unauthenticated attacker can cause denial of service for all subscribers attempting authentication through the affected AUSF.
Risk Assessment
An attacker can cause a complete denial of authentication service for all 5G network subscribers, preventing them from accessing the network.
Recommendation
Update free5GC to version 1.4.5 or later.
Other vulnerabilities in free5GC
See all- CVE-2026-30073Unknown
A vulnerability in the NssaiAvailabilitySubscriptionCreate component of free5gc v4.0.1 allows an attacker to cause a Denial of Service (DoS) via a crafted POST request.
- CVE-2026-30072Unknown
A NULL pointer dereference in the CDR processing path of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) by supplying a crafted payload.
- CVE-2026-30071Unknown
An issue in the RechargePut function of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via crafted input.
- CVE-2026-30070Unknown
An issue in the HandleGetSharedData function of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via crafted input.
- CVE-2026-30069Unknown
A NULL pointer dereference in the UDMC registration handler component of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) by supplying a crafted payload.
- CVE-2026-30068Unknown
Improper input validation in the HandleUpdate function (/sbi/parameter_provision.go) of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via crafted input.
- CVE-2026-30067Unknown
An issue in the complexQueryFilterSubprocess function in the NRF Discovery service of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via crafted input.
- CVE-2026-30064Unknown
Improper input validation in the buildFilter function (processor/processor.go) of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via crafted input.
- CVE-2026-30063Unknown
An issue in the NF Discovery endpoint of free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) via a crafted snssais query.
- CVE-2026-30060Unknown
An issue in free5gc v4.0.1 allows attackers to cause a Denial of Service (DoS) when parsing crafted SUCI data during UE registration.
Original NVD description (English source)
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.