CVE-2026-35211
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk30th percentile - higher than 30% of all known CVEs
Summary
OpenCTI GraphQL API exposes a script filter operator in its FilterOperator enum that allows authenticated users with KNOWLEDGE capability to pass unsanitized Elasticsearch Painless scripts into search queries. This can cause CPU resource exhaustion and denial of service for all users.
Risk Assessment
The organization is at risk of a Denial of Service (DoS) attack via Elasticsearch cluster CPU exhaustion, potentially rendering the OpenCTI platform unavailable and impacting access to cyber threat intelligence data.
Recommendation
Immediately upgrade OpenCTI to version 7.260401.0 or later, which includes a fix that prevents exploitation of unsafe Painless scripts.
Other vulnerabilities in OpenCTI
See all- CVE-2025-61781High
OpenCTI before version 6.8.1 contains a vulnerability in the GraphQL mutation WorkspacePopoverDeletionMutation that allows deletion of workspace-related objects (e.g., dashboards, investigation cases) without proper authorization. An attacker can supply another user's active UUID and delete the entire workspace because the API does not validate ownership.
- CVE-2026-27960Critical
In OpenCTI, versions 6.6.0 through 6.9.12, there is a privilege escalation vulnerability that can be exploited by unauthenticated attackers to query the API as any existing user, including the default admin account.
- CVE-2026-35210High
In OpenCTI prior to version 7.260326.0, an authorization bypass vulnerability 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. This enables attackers to downgrade confidence levels, remove security markings like TLP:RED, manipulate relationships, and affect STIX object types including Indicators, ThreatActors, Malware, and Reports.
- CVE-2026-35212Medium
OpenCTI versions prior to 7.260227.0 are vulnerable to XSS in the rendering of email-message observable body data. The content of the body field isn't appropriately sanitized when being rendered. Requires user interaction but could be exploited by someone sharing STIX or any of the ingester.
- CVE-2026-44730High
OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 6.9.7, an organization admin can escalate their privileges by adding a user from a different organization with higher privileges to their own organization. This is due to incorrect ACL on userEdit relationAdd. This vulnerability is fixed in 6.9.7.
Original NVD description (English source)
OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260401.0, the OpenCTI GraphQL API exposes a script filter operator in its FilterOperator enum that allows any authenticated user with the KNOWLEDGE capability to pass user-supplied Elasticsearch Painless script values directly into search queries without validation or sanitization, allowing computationally expensive scripts to consume cluster CPU resources and degrade or deny service for all users. This issue is fixed in version 7.260401.0.