# CVE-2026-28403: Textream Cross-Site WebSocket Hijacking (CSWSH) vulnerability

> A malicious web page can hijack the local WebSocket connection to remotely control teleprompter content in Textream for macOS.

- **Severity:** High 7.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L`)
- **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:** No
- **Published:** 2 Mar 2026
- **Updated:** 2 Mar 2026
- **Also known as:** GHSA-wr3v-x247-337w

## What is CVE-2026-28403?

CVE-2026-28403 is a high-severity vulnerability in f textream, published on 2 Mar 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

Textream is a free macOS teleprompter app. Prior to version 1.5.1, the `DirectorServer` WebSocket server (`ws://127.0.0.1:<httpPort+1>`) accepts connections from any origin without validating the HTTP `Origin` header during the WebSocket handshake. A malicious web page visited in the same browser session can silently connect to the local WebSocket server and send arbitrary `DirectorCommand` payloads, allowing full remote control of the teleprompter content. Version 1.5.1 fixes the issue.

Weakness: CWE-346 (Origin Validation Error)

## Which versions are affected by CVE-2026-28403?

It affects 1 product.


Products: Fka Textream.

## How do I fix CVE-2026-28403?

No fix has been published for CVE-2026-28403 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-28403 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-28403 exists.

## Other vulnerabilities in f textream

- [CVE-2026-28412](https://insights.sbomify.com/CVE-2026-28412/): Textream Vulnerable to Uncontrolled Resource Consumption (Denial of Service) (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-28403 and fix it if it is affected.

What it is: CVE-2026-28403 is a high-severity vulnerability in f textream, published on 2 Mar 2026. An attacker can exploit it over the internet without logging in, 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-2026-28403 exists.

Affected product: f textream. 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-2026-28403/ (Markdown: https://insights.sbomify.com/CVE-2026-28403/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-28403
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-28403
- OSV: https://osv.dev/vulnerability/CVE-2026-28403

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-28403/
Summaries are generated and may contain mistakes; the official description above is the record.