CVE-2026-76820

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.

CVSS 3.1

7.7CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 35% of CVEs (scores of 2026-10-25)

CWE

CWE-918

Published

2026-09-15

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

References

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

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