{"id":"CVE-2026-55784","title":"free5GC is an open-source implementation of the 5G core network","summary":"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, ke…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-362"],"vendor":"free5gc","product":"github.com/free5gc/ausf","affected":["github.com/free5gc/ausf <= 1.4.4"],"published":"2026-08-28","updated":"2026-09-08","sourceUpdated":"2026-09-08T21:11:31.703","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55784","references":[{"url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","label":"security-advisories@github.com"},{"url":"https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/advisories/GHSA-334q-h5g3-fpxv"}],"tags":["nvd","ghsa","go"],"epss":0.00253,"epssPercentile":0.17043,"aliases":["GHSA-334q-h5g3-fpxv"],"ecosystem":"go","ingestedAt":"2026-08-28T22:26:18.831Z","slug":"CVE-2026-55784","body":"## Overview\n\nfree5GC 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-55784)\n\nAffected packages:\n\n- `github.com/free5gc/ausf <= 1.4.4`\n\nSource: https://github.com/advisories/GHSA-334q-h5g3-fpxv","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}