{"id":"CVE-2026-55784","revision":"5cbd9100c812417097a0a16395b7932c","records":[{"revision":"5cbd9100c812417097a0a16395b7932c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-55784","aliases":[],"title":"free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI","description":"free5GC is an open-source implementation of the 5G core network. In version 1.4.4 and earlier, the AUSF component stores per-subscriber authentication state in a global sync.Map named AUSFContext.UePool in internal/context/context.go, keyed only by SUPI. Every request handled by internal/sbi/processor/ue_authentication.go creates an AusfUeContext, and AddAusfUeContextToPool executes ausfContext.UePool.Store(ausfUeContext.Supi, ausfUeContext), unconditionally replacing the active context for that SUPI. An attacker with access to the AUSF SBI/N12 interface can send concurrent POST /nausf-auth/v1/ue-authentications requests for the same target SUPI, causing all attempts to share one logical authentication context URL while K_aut, XRES, and EapID are repeatedly overwritten. A valid EAP-AKA' response for an earlier challenge is then checked against the latest context, causing AT_MAC verification to fail and denying authentication to the selected subscriber while the request flood continues. No fixed version is available as of this review.","state":0,"publishedAt":"2026-08-28T22:23:41.923+00:00","modifiedAt":"2026-09-01T02:04:02.754+00:00","affected":[{"ecosystem":"Vendor product","name":"free5gc","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"free5gc\",\n                    \"product\": \"free5gc\",\n                    \"versions\": [\n                        {\n                            \"version\": \"<= 1.4.4\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-55784","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-55784","identifiers":["CVE-2026-55784"]},"retained":false,"historicalAffected":[]}],"coverage":[]}