What’s Vulnerable › Vulnerabilities

CVE-2026-105090

• Severity: medium (CVSS 5.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-03 · updated 2026-10-06
• Weakness: CWE-863

Description

Formbricks before 5.4.4 and 6 before 6.0.1 allows stored XSS. The survey-level Custom Head Scripts feature did not enforce the documented Manage permission boundary. A workspace member holding only readWrite permission could configure Custom Head Scripts on a survey, an operation the documentation restricts to the Manage role. Because the configured scripts execute in the authenticated browser session of any user who opens the affected survey, a lower-privileged member can run arbitrary JavaScript (stored cross-site scripting) in the session of higher-privileged users. Fixed versions require Manage access to modify survey Custom Head Scripts.

Affected products

• formbricks: before 5.4.4; from 6.0.0 before 6.0.1 — fixed in 5.4.4, 6.0.1

How to fix

Upgrade to a fixed version: formbricks 5.4.4, 6.0.1. Check the vendor advisory for mitigations.

References

• https://github.com/formbricks/formbricks/pull/9432
• https://github.com/formbricks/formbricks/releases/tag/5.4.4
• https://github.com/formbricks/formbricks/releases/tag/6.0.1
• https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html
• https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html

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