CVE-2026-8731 — Open5GS Denial of Service

title: CVE-2026-8731 - Open5GS NRF Denial of Service
id: scw-2026-05-17-ai-1
status: experimental
level: high
description: |
  Detects the specific exploit pattern for CVE-2026-8731 targeting the Open5GS NRF component. The vulnerability lies in the ogs_sbi_client_add function where manipulation of the 'client_pool' argument in a POST request to the NRF subscription endpoint can lead to a denial of service. This rule specifically looks for POST requests to the NRF subscription URI containing the vulnerable 'client_pool' parameter.
author: SCW Feed Engine (AI-generated)
date: 2026-05-17
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-8731/
tags:
  - attack.impact
  - attack.t1499
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '/nrfnrf/v1/nrfnrf/subscribe'
      cs-method:
          - 'POST'
      cs-uri-query|contains:
          - 'client_pool='
  condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse