What’s Vulnerable › Vulnerabilities

CVE-2026-35210: OpenCTI: Authorization Bypass via `synchronized-upsert` HTTP Header Injection

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-08 · updated 2026-10-25
• Weakness: CWE-639

Description

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260326.0, an authorization bypass vulnerability in OpenCTI allows any authenticated user with KNOWLEDGE_KNUPDATE permission to bypass Confidence Level validation and Object Marking restrictions by injecting the synchronized-upsert: true HTTP header, enabling attackers to downgrade confidence levels, remove security markings such as TLP:RED, manipulate relationships, and affect STIX object types including Indicators, ThreatActors, Malware, and Reports. This issue is fixed in version 7.260326.0.

Affected products

• OpenCTI-Platform opencti: before 7.260326.0 — fixed in 7.260326.0

How to fix

Upgrade to a fixed version: OpenCTI-Platform opencti 7.260326.0. Check the vendor advisory for mitigations.

References

• https://github.com/OpenCTI-Platform/opencti/commit/134531ddf5ecf741006b7f0870b7c36711b96540
• https://github.com/OpenCTI-Platform/opencti/pull/14243
• https://github.com/OpenCTI-Platform/opencti/releases/tag/7.260326.0
• https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-36fr-4m54-94mj

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