{"id":"CVE-2026-55784","state":"PUBLISHED","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.","publishedAt":"2026-08-28T22:23:41.923Z","updatedAt":"2026-09-01T02:04:02.754Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["free5gc free5gc"],"affected":[{"vendor":"free5gc","product":"free5gc","versions":[{"version":"<= 1.4.4","status":"affected"}]}],"references":["https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55784.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55784","state":"PUBLISHED","datePublished":"2026-08-28T22:23:41.923Z","dateUpdated":"2026-09-01T02:04:02.754Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-17T14:40:28.379Z"},"containers":{"cna":{"title":"free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"free5gc","product":"free5gc","versions":[{"version":"<= 1.4.4","status":"affected"}]}],"references":[{"url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","name":"https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","description":"CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-28T22:23:41.923Z"},"source":{"advisory":"GHSA-334q-h5g3-fpxv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-01T02:03:37.064988Z","id":"CVE-2026-55784","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-01T02:04:02.754Z"}}]}}}