CVE-2026-21887: OpenCTI has Semi-Blind SSRF via Unvalidated External URL in Data Ingestion Feature

June 22, 2026

The OpenCTI platform’s data ingestion feature accepts user-supplied URLs without validation and uses the Axios HTTP client with its default configuration (allowAbsoluteUrls: true). This allows attackers to craft requests to arbitrary endpoints, including internal services, because Axios will accept and process absolute URLs.

This results in a semi-blind SSRF, as responses may not be fully visible but can still impact internal systems.

References

github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-ffm6-vvph-g5f5
github.com/advisories/GHSA-ffm6-vvph-g5f5
github.com/pypa/advisory-database/tree/main/vulns/pycti/PYSEC-2026-118.yaml
nvd.nist.gov/vuln/detail/CVE-2026-21887

Code Behaviors & Features

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