free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NRF root SBI endpoint POST /oauth2/token contains a parser-level type-confusion bug family. The handler in NFs/nrf/internal/sbi/api_accesstoken.go reflects over models.NrfAccessTokenAccessTokenReq, special-cases only plain string and NrfNfManagementNfType fields, and treats every other field as if it were a single models.PlmnId. The parsed *models.PlmnId is then assigned with reflect.Value.Set() to whichever field name the attacker put in the form body, which panics whenever the destination field's real type is incompatible (slice, different struct, primitive). Gin recovery converts each panic into HTTP 500, but the endpoint remains remotely panicable from a single unauthenticated form-encoded request and is repeatedly triggerable. This vulnerability is fixed in 4.2.2.
History

Thu, 28 May 2026 17:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*

Thu, 28 May 2026 03:45:00 +0000

Type Values Removed Values Added
First Time appeared Free5gc
Free5gc free5gc
Vendors & Products Free5gc
Free5gc free5gc

Wed, 27 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 27 May 2026 16:30:00 +0000

Type Values Removed Values Added
Description free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NRF root SBI endpoint POST /oauth2/token contains a parser-level type-confusion bug family. The handler in NFs/nrf/internal/sbi/api_accesstoken.go reflects over models.NrfAccessTokenAccessTokenReq, special-cases only plain string and NrfNfManagementNfType fields, and treats every other field as if it were a single models.PlmnId. The parsed *models.PlmnId is then assigned with reflect.Value.Set() to whichever field name the attacker put in the form body, which panics whenever the destination field's real type is incompatible (slice, different struct, primitive). Gin recovery converts each panic into HTTP 500, but the endpoint remains remotely panicable from a single unauthenticated form-encoded request and is repeatedly triggerable. This vulnerability is fixed in 4.2.2.
Title free5GC: NRF POST /oauth2/token structured-form parser type-confusion panic family (Reflect.Set on incompatible types)
Weaknesses CWE-20
CWE-755
CWE-843
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-05-27T15:43:34.136Z

Updated: 2026-05-27T17:50:51.669Z

Reserved: 2026-05-05T19:00:06.023Z

Link: CVE-2026-44325

cve-icon Vulnrichment

Updated: 2026-05-27T17:49:58.523Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-27T17:16:37.910

Modified: 2026-05-28T16:51:24.287

Link: CVE-2026-44325

cve-icon Redhat

No data.