CVE-2026-71416 Headroom vulnerable to Cross-Site WebSocket Hijacking (CSWSH)
Attackers can hijack WebSocket sessions to perform unauthorized LLM requests and access API keys due to missing Origin header validation.
- 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-2026-71416?
CVE-2026-71416 is a high-severity vulnerability in headroomlabs-ai headroom, published on 11 Sep 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
Headroom compresses data before the data reaches a large language model. Prior to version 0.35.0, the Headroom WebSocket server does not validate the `Origin` header of incoming client WebSocket requests before forwarding the request to the upstream server, allowing malicious WebSocket clients to perform arbitrary LLM requests without authentication. This can be exploited by a malicious WebSocket client executed in a traditional or headless browser such as lightpanda, if the browser has access to the Headroom proxy and the OpenAI API key is stored in the `OPENAI_API_KEY` environment variable. Version 0.35.0 fixes the issue.
Which versions are affected by CVE-2026-71416?
3 open source packages ship an affected version, including headroom-ai.
| Package | Affected | Fixed in |
|---|---|---|
headroom-ai PyPI | All versions | 0.35.0 |
headroom-ai PyPI | All versions | 0.35.0 |
headroom-ai PyPI | All versions | 0.35.0 |
How do I fix CVE-2026-71416?
Upgrade headroom-ai to 0.35.0 or later.
Is CVE-2026-71416 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-71416 exists.
Sources
Also known as GHSA-h46j-26q3-rggf, PYSEC-2026-4220.