CVE-2026-76820 OpenCTI: Synchronizer SSRF: stream fetch has no URL validation
Authenticated users can exploit missing URL validation in the synchronizer to access internal services and cloud metadata, enabling network scanning and data disclosure.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-76820?
CVE-2026-76820 is a high-severity server-side request forgery vulnerability in OpenCTI-Platform opencti, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-918
Which versions are affected by CVE-2026-76820?
How do I fix CVE-2026-76820?
No fix has been published for CVE-2026-76820 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-76820 being exploited?
There is no known exploitation of CVE-2026-76820 in the wild and no public exploit code.
Sources
Also known as GHSA-f6pj-3m32-q934.