CVE-2026-55784

{
  "id": "CVE-2026-55784",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-28T23:17:07.517",
  "lastModified": "2026-10-20T16:13:56.927",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "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": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "free5gc",
          "product": "free5gc",
          "versions": [
            {
              "version": "<= 1.4.4",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-09-01T02:03:37.064988Z",
          "id": "CVE-2026-55784",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/free5gc/free5gc/security/advisories/GHSA-334q-h5g3-fpxv",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}