Auth bypass in Citeum Opencti
CVE-2026-35210
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (26.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Citeum Opencti
- Opencti-Platform Opencti — versions < 7.260326.0
Weakness classification (CWE)
References
- github.com/OpenCTI-Platform/opencti/commit/134531ddf5ecf741006b7f0870b7c36711b9… (Patch)
- github.com/OpenCTI-Platform/opencti/pull/14243 (Patch, Issue Tracking)
- github.com/OpenCTI-Platform/opencti/releases/tag/7.260326.0 (Product, Release Notes)
- github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-36fr-4m54-94mj (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-35210?
- CVE-2026-35210 is a high-severity vulnerability in Citeum Opencti, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 7.1/10. Published 2026-07-08.
- How severe is CVE-2026-35210?
- High severity. CVSS v3 base score is 7.1 out of 10.