OpenCTI has Semi-Blind SSRF via Unvalidated External URL in Data Ingestion Feature

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-21887: 0.23% estimated exploitation activity in the next 30 days; percentile 13.32 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Impact OpenCTI’s data ingestion feature can allow an attacker to make the application send HTTP requests to arbitrary internal or external endpoints. This means an attacker could reach internal services that are not exposed publicly, such as Elasticsearch, Redis, or RabbitMQ, and potentially extract sensitive data or manipulate internal components. In cloud environments, the attacker could target metadata services like AWS, Azure, or GCP to obtain credentials and configuration details, which could lead to full compromise of the infrastructure.…

Published by the source

22 Jun 2026, 17:01 UTC

Last modified by the source

22 Jun 2026, 17:15 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-ffm6-vvph-g5f5

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-ffm6-vvph-g5f5

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# Patch Next advisory brief: CVE-2026-21887

Advisory: OpenCTI has Semi-Blind SSRF via Unvalidated External URL in Data Ingestion Feature
IDs: CVE-2026-21887, GHSA-ffm6-vvph-g5f5
Record: https://patchnext.com/advisories/cve-2026-21887 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pycti 6.8.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pycti: affected < 6.8.16; fixed in 6.8.16

## Suggested inspection (read-only)
- `python -m pip show pycti`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pycti.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-ffm6-vvph-g5f5 (OSV record GHSA-ffm6-vvph-g5f5 lists affected ranges: PyPI pycti >=0 <6.8.16 (fixed))
- Verified: https://github.com/advisories/GHSA-ffm6-vvph-g5f5 (GitHub-reviewed advisory GHSA-ffm6-vvph-g5f5 lists affected ranges: PyPI pycti >=0 <6.8.16)

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