{"cve":"CVE-2026-55784","nvd":{"published":"2026-08-28T23:17:07.517","modified":"2026-10-20T16:13:56.927","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-362"],"references":["https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:56:58.798400159+00:00"},"epss":{"cve":"CVE-2026-55784","score":0.00419,"percentile":0.3589,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-334q-h5g3-fpxv","url":"https://osv.dev/vulnerability/GHSA-334q-h5g3-fpxv","summary":"free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI","modified":"2026-09-02T19:55:41.418108937Z","packages":[{"ecosystem":"Go","name":"github.com/free5gc/ausf","purl":"pkg:golang/github.com/free5gc/ausf","ranges":["<=1.4.4"],"fixed":[]}]},{"id":"GO-2026-6326","url":"https://osv.dev/vulnerability/GO-2026-6326","summary":"free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI in github.com/free5gc/ausf","modified":"2026-09-02T19:45:13.187644264Z","packages":[{"ecosystem":"Go","name":"github.com/free5gc/ausf","purl":"pkg:golang/github.com/free5gc/ausf","ranges":["all versions"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}