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UE Downlink Redirection via Forged PDUSessionResourceSetupResponse

High
gruyaume published GHSA-qfxw-v8qx-vj3v May 6, 2026

Package

gomod github.com/ellanetworks/core (Go)

Affected versions

< 1.10.0

Patched versions

1.10.0

Description

Summary

A radio with a valid NG Setup can send a forged PDUSessionResourceSetupResponse carrying any UE's AMF-UE-NGAP-ID. Ella Core does not verify the message arrived on the SCTP association bound to that UE's logical NG-connection, then creates a GTP tunnel towards that radio.

Impact

Downlink user-plane traffic for the targeted UE is redirected to the attacker's radio.

Fix

UE context lookups are now scoped to the sending radio's SCTP association.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

CVE ID

CVE-2026-44473

Weaknesses

Improperly Implemented Security Check for Standard

The product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique. Learn more on MITRE.

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. Learn more on MITRE.

Credits