Is CVE-2026-35210 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-35210 being exploited in the wild.

How severe is CVE-2026-35210?

High severity, with a CVSS score of 7.1, published 8 July 2026.

Which products and versions are affected?

pycti (PyPI) ECOSYSTEM:introduced=0,fixed=7.260326.0.

Is there a fix for CVE-2026-35210?

Yes. pycti (PyPI): upgrade to 7.260326.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-35210 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-35210?

Check whether you run pycti (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-35210: Filigran OpenCTI authorization bypass via synchronized-upsert header

CVE-2026-35210 · Severity: high · CVSS 7.1 · Published 2026-07-08

OpenCTI is an open-source platform used by organizations to manage and share cyber threat intelligence. A security flaw allows authorized users to bypass data protection rules, such as 'TLP:RED' markings or confidence levels, by manipulating technical web headers. This could allow an insider or a compromised account to downgrade the reliability of threat data or remove sensitivity labels, potentially leading to the unauthorized disclosure or corruption of critical intelligence.

Technologies: pycti (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-35210 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-35210 being exploited in the wild.
How severe is CVE-2026-35210?: High severity, with a CVSS score of 7.1, published 8 July 2026.
Which products and versions are affected?: pycti (PyPI) ECOSYSTEM:introduced=0,fixed=7.260326.0.
Is there a fix for CVE-2026-35210?: Yes. pycti (PyPI): upgrade to 7.260326.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-35210 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-35210?: Check whether you run pycti (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

pycti (PyPI): upgrade to 7.260326.0 or later
```
pip install "pycti>=7.260326.0"
```

Technical details

An authorization bypass vulnerability exists in OpenCTI due to improper validation of the 'synchronized-upsert: true' HTTP header. Authenticated users possessing the 'KNOWLEDGE_KNUPDATE' permission can inject this header to bypass Confidence Level validation and Object Marking restrictions (such as TLP markings). This allows an attacker to downgrade confidence levels, remove security markings, and manipulate relationships across various STIX object types, including Indicators, Threat Actors, and Reports. The root cause is that the 'synchronized-upsert' functionality, intended for full synchronization by administrative/system processes, was accessible to standard users. The issue is fixed in version 7.260326.0.

Affected products

Filigran OpenCTI < 7.260326.0

Identifiers

CVE-2026-35210
PYSEC-2026-3445

Timeline

2026-01-28: other: Pull request initiated to fix header usage
2026-03-19: patched: Fix committed to master branch
2026-03-26: advisory: Release 7.260326.0 published
2026-07-08: disclosed: CVE-2026-35210 published

References

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