---
id: "CVE-2026-116679"
kind: "vulnerability"
aliases: ["CVE-2026-116679", "GHSA-5cp7-fp4j-wwcv"]
title: "Neko: Authorization bypass in legacy WebRTC input handling"
severity: "medium"
cvss: 5.4
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "github.com/m1k1o/neko/server", "fixed": ["0.0.0-20260805142851-395ca1a6f62b"], "affected": ">= 0.0.0-20250401220545-fe94c999c6af, < 0.0.0-20260805142851-395ca1a6f62b", "ecosystem": "go"}]
ecosystems: ["go"]
tags: ["cwe-863", "docker", "neko", "other", "self-hosted", "webrtc"]
not_affected_if: ["auth-required", "default-config"]
published_at: "2026-10-27T18:17:35+00:00"
first_seen_at: "2026-10-27T18:32:59+00:00"
updated_at: "2026-10-27T21:09:20+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116679", "first_seen_at": "2026-10-27T18:32:59+00:00"}, {"source": "ghsa", "url": "https://github.com/advisories/GHSA-5cp7-fp4j-wwcv", "first_seen_at": "2026-10-27T21:09:20+00:00"}]
---

# Neko: Authorization bypass in legacy WebRTC input handling

Neko is a self-hosted virtual browser that runs in Docker and streams over WebRTC. In versions 3.0.0 through 3.1.4, a host-check bug in legacy mode with implicit hosting lets an authenticated room member send mouse and keyboard input over the legacy data channel even when controls are locked.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:github.com/m1k1o/neko/server affected >= 0.0.0-20250401220545-fe94c999c6af, < 0.0.0-20260805142851-395ca1a6f62b fixed 0.0.0-20260805142851-395ca1a6f62b

## How to check

- Check the Neko version in the running image tag, `3.1.4` or earlier means affected
- Look for `legacy` mode and `session.implicit_hosting` enabled in the Neko configuration
- unknown whether the sources list other specific checks

## Fix

- Upgrade Neko to `3.1.5` or later
- unknown whether a configuration-only workaround exists

## Timeline

- 2026-10-27T18:32:59+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-116679
- 2026-10-27T21:09:20+00:00 ghsa https://github.com/advisories/GHSA-5cp7-fp4j-wwcv

## From the sources

### Impact

When legacy mode is enabled and `session.implicit_hosting` is enabled, the legacy WebRTC data channel incorrectly authorizes input events due to a logic error in `LegacyIsHost()`.

As a result, an authenticated room member may be able to send mouse and keyboard input through the legacy WebRTC control channel even when controls are locked or the member would otherwise not be authorized through the modern control API.

The issue affects only the legacy WebRTC input path. The modern HTTP/WebSocket control path correctly enforces authorization checks and is not affected.

To exploit this issue, an attacker must:

* Be authenticated as a room member.
* Successfully establish a WebRTC connection.
* Access a deployment using the legacy WebRTC input handler.

No unauthenticated access or privilege escalation outside the application is possible.

### Patches

The issue has been fixed in **[v3.1.5](https://github.com/m1k1o/neko/releases/tag/v3.1.5)** by correcting the authorization logic in the legacy WebRTC handler.

Users should upgrade to **[v3.1.5](https://github.com/m1k1o/neko/releases/tag/v3.1.5)** or later. Fix: *[395ca1a](https://github.com/m1k1o/neko/commit/395ca1a6f62b7b0e270e654d366a2d57b8042efd)*

### Workarounds

Users who cannot immediately upgrade can mitigate the issue by one of the following:

* Disable legacy mode if it is not required.
* Disable implicit hosting (`session.implicit_hosting=false`).
* Restrict access to trusted authenticated users.

### Credits

Thanks to @KasperBuilds for responsibly disclosing this vulnerability and reaching out directly. This contribution helped strengthen the project, and the whole community benefits from it.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_