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OpenctiApplication · Citeum

CVE-2026-21887

HIGH · 7.7 CVSS v3.1 Published 2026-03-12
Fix available
A fix is available. Upgrade to 6.8.16 or later.
See remediation →
83/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 6.8.16, 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. This vulnerability is fixed in 6.8.16.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

OpenCTI's data ingestion feature accepts user-supplied URLs without validation and uses Axios with its default allowAbsoluteUrls: true configuration. This allows attackers to craft requests to arbitrary endpoints, including internal services, resulting in a semi-blind SSRF vulnerability where responses may not be fully visible but can still impact internal systems. The vulnerability is fixed in version 6.8.16.

MitigationUpgrade to OpenCTI version 6.8.16 or later. Additionally, implement URL allowlist validation and configure Axios with allowAbsoluteUrls: false to prevent requests to arbitrary URLs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpenctiApplication
Affected:< 6.8.16

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify OpenCTI installation and version
    Run 'docker ps' or check your container orchestration (Kubernetes, etc.) to find the OpenCTI container, then check the version using 'docker inspect <container_id>' or check the image tag
    Affected if The installed version is below 6.8.16 (e.g., 6.8.0, 6.7.x, etc.)
  2. Locate the OpenCTI data ingestion configuration
    Check the OpenCTI installation directory for configuration files related to data ingestion, typically in the 'external-importers' or 'connectors' section of the configuration
    Affected if Data ingestion connectors are configured and actively importing from external sources
  3. Verify Axios client configuration
    Search the OpenCTI source code or configuration for Axios instances, specifically looking for 'allowAbsoluteUrls' setting. Check files under 'external-import' or connector directories where HTTP requests are made
    Affected if Axios is configured with allowAbsoluteUrls: true (the default) or the setting is not explicitly set to false
  4. Audit data ingestion sources
    Review the list of configured data ingestion feeds/importers in the OpenCTI UI under 'Data > Ingestion' or via the API, checking for any sources that accept user-supplied URLs
    Affected if Any data ingestion source accepts user-controlled URLs as input for external data fetching

You are affected if OpenCTI version is below 6.8.16 AND the data ingestion feature is actively used with user-supplied URLs, since the vulnerable Axios default configuration allows requests to arbitrary URLs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.8.16 or later
Fixed in 6.8.16
Interim mitigation

Upgrade to OpenCTI version 6.8.16 or later. Additionally, implement URL allowlist validation and configure Axios with allowAbsoluteUrls: false to prevent requests to arbitrary URLs.

Recommended fix High confidence

6.8.16

  1. Backup your current OpenCTI installation and data before upgrading
  2. Upgrade OpenCTI to version 6.8.16 or later
  3. Verify the upgrade was successful by checking the OpenCTI version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Opencti Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-21887 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data