CVE-2025-26621

OpenCTI vulnerable to Denial of Service through web hook

MEDIUM
6.8
CVSS Score
Published: May 19, 2025 at 04:01 PM UTC
Updated: June 17, 2026 at 09:02 AM UTC
2 products affected across 2 vendorsOpenctiOpencti

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Severity
MEDIUM6.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

OpenCTI 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.5.2
Affected range stops below 6.5.2, so it looks safe — our inference, not a vendor statement
v < 6.5.2
Affected range stops below 6.5.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-94CWE-1321

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