CVE-2026-76820highCWE-918

CVE-2026-76820: high-severity vulnerability in OpenCTI-Platform opencti

OpenCTI: Synchronizer SSRF: stream fetch has no URL validation

Published · Updated

Follow this CVE+ Monitor opencti

E-mail alert when it lands in KEV, gets a public PoC or its score goes up.

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.7epss 0.4%
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/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Affected products
OpenCTI-Platform · opencti
Related CVEs — OpenCTI-Platform opencti

In the same product, most dangerous first.

CVE-2026-27960CRITICALOpenCTI privilege escalation and unauthenticated access via default admin accountEPSS 7.1%CVE-2026-39980CRITICALOpenCTI affected by RCE via notifier templateEPSS 1.4%CVE-2025-24977CRITICALOpenCTI has remote code execution and sensitive secrets exposed through web hookEPSS 0.9%CVE-2024-45404HIGHOpenCTI's lack of Rate Limit lead to OTP brute forcingEPSS 0.6%CVE-2026-35211MEDIUMOpenCTI: Elasticsearch Painless Script Injection via GraphQL `script` filter operator allows authenticated user to exfiltrate data and cause DoSEPSS 0.5%CVE-2026-76821HIGHOpenCTI: User-Controlled ReDoS in JSON Ingestion MapperEPSS 0.5%