What is the CVSS score of EUVD-2026-20509?

EUVD-2026-20509 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

How to fix or mitigate EUVD-2026-20509?

Within 24 hours: Identify all 5G deployments running OpenAirInterface 2.2.0 AUSF and document network topology/access points. Within 7 days: Implement network segmentation to restrict NAS PDU traffic to trusted 5G RAN sources only; enable detailed logging of UplinkNASTransport messages for anomaly detection. Within 30 days: Evaluate upgrade to OpenAirInterface 3.x release track or transition to alternative AUSF vendors; coordinate with vendor on patch timeline for 2.2.0 branch.

EUVD-2026-20509

| CVE-2026-30075 HIGH

Classic Buffer Overflow (CWE-120)

2026-04-08 mitre

Buffer Overflow

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

EUVD ID Assigned

Apr 08, 2026 - 17:16 euvd

EUVD-2026-20509

Analysis Generated

Apr 08, 2026 - 17:16 vuln.today

CVE Published

Apr 08, 2026 - 00:00 nvd

HIGH 7.5

DescriptionCVE.org

OpenAirInterface Version 2.2.0 has a Buffer Overflow vulnerability in processing UplinkNASTransport containing Authentication Response containing a NAS PDU with oversize response (For example 100 byte). The response is decoded by AMF and passed to the AUSF component for verification. AUSF crashes on receiving this oversize response. This can prohibit users from further registration and verification and can cause Denial of Services (DoS).

AnalysisAI

Buffer overflow in OpenAirInterface 2.2.0 AUSF component crashes service when processing oversized NAS PDU Authentication Response via UplinkNASTransport messages. Unauthenticated remote attackers can send malformed authentication responses (e.g., 100-byte payloads exceeding expected bounds) triggering AUSF component crash, preventing legitimate user registration and verification. Affects 5G core network deployments using OpenAirInterface AUSF. No public exploit identified at time of analysis. CVSS 7.5 High severity due to network-accessible denial of service without authentication requirements.

Technical ContextAI

CWE-120 buffer overflow occurs in AUSF component's NAS PDU decoder when processing Authentication Response messages exceeding expected buffer size. AMF forwards oversized response to AUSF without validation, triggering memory corruption and component crash. Affects cn5g-ausf implementation in OpenAirInterface 5G Core Network stack.

RemediationAI

Review vendor issue tracker at https://gitlab.eurecom.fr/oai/cn5g/oai-cn5g-ausf/-/issues/6 for upstream fix status. Upstream fix available (issue #6); released patched version not independently confirmed at time of analysis. Recommended immediate actions: implement network-level input validation filtering oversized NAS PDU messages before reaching AUSF component, deploy rate limiting on UplinkNASTransport processing, monitor AUSF component health with automatic restart capability. For production 5G core deployments, isolate AUSF component with strict firewall rules permitting only authenticated AMF traffic. Consult official advisory at https://nvd.nist.gov/vuln/detail/CVE-2026-30075 for vendor updates. Subscribe to OpenAirInterface security notifications for patched release announcements.