---
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: 0.17052
aliases:
  - GHSA-334q-h5g3-fpxv
ecosystem: go
ingestedAt: '2026-08-28T22:26:18.831Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55784)

Affected packages:

- `github.com/free5gc/ausf <= 1.4.4`

Source: https://github.com/advisories/GHSA-334q-h5g3-fpxv