Cyber Resilience

CVE-2026-35210

Access Control in Citeum Opencti ≤ 7.260326.0

Access Control
Published
08 July 2026
Modified
13 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
EPSS Score 0.0026 17th percentile
Risk Priority 53 floored blend · peak EPSS

Summary

CVE-2026-35210 is a high-severity Authorization Bypass Through User-Controlled Key (CWE-639) vulnerability in Citeum Opencti. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-639CWE-863

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
attack.mitre.org →
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-35211Same product: Citeum Opencti
CVE-2025-61781Same product: Citeum Opencti
CVE-2025-46732Same product: Citeum Opencti
CVE-2026-21886Same product: Citeum Opencti
CVE-2024-45805Same product: Citeum Opencti
CVE-2025-24887Same product: Citeum Opencti
CVE-2024-26139Same product: Citeum Opencti
CVE-2024-37155Same product: Citeum Opencti
CVE-2026-44730Same product: Citeum Opencti
CVE-2026-27960Same product: Citeum Opencti

Affected Assets

citeum
opencti
≤ 7.260326.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

Enforcing approved authorizations on every access request structurally stops a user-controlled key from reaching another user's data.

AC-24 Access Control Decisions good match

Requiring explicit access-control decisions on each request blocks unauthorized key-driven access.

AC-25 Reference Monitor good match

A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.

AC-6 Least Privilege partial match

Least-privilege restrictions limit the scope of data reachable even if a key check is bypassed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 full match
prevents

Enforcing authorization policy and least privilege directly blocks user-controlled key tampering that bypasses access checks.

PR.IR-01 mostly match
prevents

Logical access controls prevent unauthorized data access that results from missing authorization checks on object references.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect missing authorization checks but does not prevent the weakness in production.

A.8.3 Information access restriction mostly match
prevents

Information access restriction explicitly enforces that users may only retrieve data they are authorized to see, directly addressing user-controlled key bypass.

A.5.15 Access control partial match
prevents

Access control policy directly requires enforcement of authorization rules that prevent unauthorized access via manipulated keys.

A.5.18 Access rights partial match
prevents

Managing access rights includes ensuring users can only access their own records and not bypass authorization by altering identifiers.

A.8.2 Privileged access rights partial match
mitigates

Privileged access rights control restricts what data each user may access, mitigating direct object reference attacks.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes authorization design but does not itself implement runtime access checks.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References