CVE-2026-8266 — Open5GS Denial of Service

title: CVE-2026-8266 - Open5GS SMF Denial of Service Attempt
id: scw-2026-05-11-ai-1
status: experimental
level: high
description: |
  This rule detects attempts to exploit CVE-2026-8266 by targeting the vulnerable gsm_build_pdu_session_establishment_accept function within the SMF component of Open5GS. The detection looks for specific URI paths and query parameters indicative of the exploit targeting the affected file and function. This is a critical detection for initial access via this vulnerability.
author: SCW Feed Engine (AI-generated)
date: 2026-05-11
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-8266/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '/smf/gsm-build.c'
      cs-method:
          - 'POST'
      cs-uri-query|contains:
          - 'gsm_build_pdu_session_establishment_accept'
  condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse