# CVE-2026-105090: Cross-site scripting in Formbricks

> A lower-privileged user can inject malicious scripts via survey head scripts, executing arbitrary JavaScript in other users' sessions.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 3 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-q9hg-xqvp-x2xv

## What is CVE-2026-105090?

CVE-2026-105090 is a medium-severity cross-site scripting vulnerability in Formbricks, published on 3 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-105090?


## How do I fix CVE-2026-105090?

No fix has been published for CVE-2026-105090 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-105090 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105090 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105090 and fix it if it is affected.

What it is: CVE-2026-105090 is a medium-severity cross-site scripting vulnerability in Formbricks, published on 3 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-105090 exists.

Affected product: Formbricks. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105090/ (Markdown: https://insights.sbomify.com/CVE-2026-105090/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105090
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105090
- OSV: https://osv.dev/vulnerability/CVE-2026-105090

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105090/
Summaries are generated and may contain mistakes; the official description above is the record.