CVE-2026-35212 OpenCTI has XSS in the rendering of email-message observable body data
Attackers can inject malicious scripts via email observable bodies, leading to session theft and CSRF attacks in OpenCTI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-35212?
CVE-2026-35212 is a medium-severity cross-site scripting vulnerability in OpenCTI-Platform opencti, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. 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. Does require user interaction but could be exploited by someone sharing stix or any of the ingester. This could lead to CSRF and then large scale session theft. Version 7.260227.0 contains a fix.
Weakness: CWE-79
Which versions are affected by CVE-2026-35212?
1 open source package ship an affected version, including pycti. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pycti PyPI | All versions | 7.260227.0 |
Products include Citeum Opencti.
How do I fix CVE-2026-35212?
Upgrade pycti to 7.260227.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-35212 being exploited?
There is no known exploitation of CVE-2026-35212 in the wild and no public exploit code.
Other vulnerabilities in OpenCTI-Platform opencti
- CVE-2026-27960 OpenCTI privilege escalation and unauthenticated access via default admin account
- CVE-2026-39980 OpenCTI affected by RCE via notifier template
- CVE-2025-24977 OpenCTI has remote code execution and sensitive secrets exposed through web hook
- CVE-2024-26139 OpenCTI Authenticated Privilege Escalation
- CVE-2024-45404 OpenCTI's lack of Rate Limit lead to OTP brute forcing
Sources
Also known as GHSA-rg6r-x26x-63vq, PYSEC-2026-203.