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.
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History
Wed, 05 Aug 2026 03:30:00 +0000
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ssvc
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Fri, 31 Jul 2026 21:45:00 +0000
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Free5gc
Free5gc ausf Free5gc free5gc |
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Free5gc
Free5gc ausf Free5gc free5gc |
Fri, 31 Jul 2026 20:15:00 +0000
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| Description | 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. | |
| Title | free5GC AUSF: null byte injection in supiOrSuci causes HTTP 500 internal service failure | |
| Weaknesses | CWE-20 | |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-07-31T20:12:57.932Z
Updated: 2026-08-03T16:26:59.863Z
Reserved: 2026-06-09T18:13:07.263Z
Link: CVE-2026-53551
Updated: 2026-08-03T16:18:58.095Z
Status : Received
Published: 2026-07-31T20:16:51.697
Modified: 2026-08-03T17:16:38.093
Link: CVE-2026-53551
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