# CVE-2026-76820

## Summary

- **CVE ID:** CVE-2026-76820
- **Severity:** HIGH
- **CVSS Score:** 7.7 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N)
- **CWE:** CWE-918
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 16, 2026

## Description

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260701.0, the synchronizerFetch GraphQL query called fetchRemoteStreams after checking only that a remote stream URL used HTTP or HTTPS. The backend did not apply the ingestion deny list or reject private, loopback, and link-local destinations, allowing an authenticated account with the INGESTION capability to make OpenCTI request internal services and cloud metadata endpoints. Returned connection errors could distinguish open HTTP ports, open non-HTTP ports, and closed ports, enabling internal network scanning, while compatible endpoint responses could disclose internal data. This issue is fixed in version 7.260701.0.

## Affected Products

- OpenCTI-Platform — opencti (< 7.260701.0)

## References

- [CNA](https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-f6pj-3m32-q934)
- [CNA](https://github.com/OpenCTI-Platform/opencti/pull/16617)
- [CNA](https://github.com/OpenCTI-Platform/opencti/commit/6c1114ce8ce8f3a9d9b8c82dfff3a3a462e5dc1f)
- [CNA](https://github.com/OpenCTI-Platform/opencti/releases/tag/7.260701.0)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.30%
- **EPSS Percentile:** 23.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._