CVE-2025-26621
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 · uneditedOpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to version 6.5.2, any user with the capability manage customizations can edit webhook that will execute javascript code. This can be abused to cause a denial of service attack by prototype pollution, making the node js server running the OpenCTI frontend become unavailable. Version 6.5.2 fixes the issue.
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 · high confidenceOpenCTI versions prior to 6.5.2 allow users with the 'manage customizations' capability to edit webhooks that execute JavaScript code. This can be exploited through prototype pollution to cause denial of service, rendering the Node.js server running the OpenCTI frontend unavailable.
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< 6.5.2CVSS 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
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Check OpenCTI versionIdentify the installed OpenCTI version in your environment and compare it to the affected range (versions prior to 6.5.2)Affected if Installed version is less than 6.5.2
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Identify users with 'manage customizations' capabilityReview role configurations and user permissions to determine which users or roles have the 'manage customizations' capability enabledAffected if Any user account has the 'manage customizations' capability assigned
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Inspect custom webhook configurationsExamine existing webhook settings in the OpenCTI customization or integration section, specifically looking for webhooks that contain custom JavaScript codeAffected if Custom webhooks with JavaScript execution are configured in the system
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Check for Node.js service disruptionVerify the availability and stability of the Node.js server running the OpenCTI frontend; look for unexpected crashes, unavailability, or error logsAffected if The OpenCTI Node.js frontend server is unavailable or exhibits denial of service symptoms
A user is affected if they are running OpenCTI version less than 6.5.2 and have users with the 'manage customizations' capability that can edit webhooks containing JavaScript code.
Generated from the published advisory. Verify against your own configuration.
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 · scoped6.5.2
Upgrade OpenCTI to version 6.5.2 or later. As a temporary measure, restrict the 'manage customizations' capability to only highly trusted administrators until the upgrade can be completed.
6.5.2
- Check current OpenCTI version using platform administrative interface or deployment configuration
- Plan upgrade to version 6.5.2 or later following standard OpenCTI upgrade procedures
- For Docker deployments: Update the Docker image tag to the fixed version (6.5.2 or later) in docker-compose.yml or your deployment configuration
- Pull the new container images
- Recreate containers to apply the update
- Verify the upgrade was successful by checking the platform version and ensuring core functionality works
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-26621 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-26621 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data