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CVE

CVE-2025-26621

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to version 6.

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.

HIGH · CVSS 7.6 EPSS 0.00727
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
CWE-94Improper Control of Generation of Code ('Code Injection')
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Affected Products & Versions

1
citeum opencti< 6.5.2
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI pycti fixed in 6.5.2
▣

Scoring & Timeline

7.6
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD19 May 2025 · 04:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-gq63-jm3h-374pVendor Advisory
https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-mf88-g2wq-p7qmNot Applicable
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