Dozzle is a realtime log viewer for docker containers. Prior to 10.5.2, he WebSocket upgrader for the /exec and /attach endpoints uses CheckOrigin: func(r *http.Request) bool { return true }, accepting upgrade requests from any origin. Combined with the JWT cookie using SameSite: Lax, this enables Cross-Site WebSocket Hijacking (CSWSH). An attacker hosting a page on a same-site origin (e.g., a sibling subdomain, or another service on localhost) can initiate a WebSocket connection to the exec endpoint that carries the victim's valid JWT cookie, gaining interactive shell access in any container the victim is authorized to access. This vulnerability is fixed in 10.5.2.

Affected: Go: github.com/amir20/dozzle

## Summary

The WebSocket upgrader for the `/exec` and `/attach` endpoints uses `CheckOrigin: func(r *http.Request) bool { return true }`, accepting upgrade requests from any origin. Combined with the JWT cookie using `SameSite: Lax`, this enables Cross-Site WebSocket Hijacking (CSWSH) — **even when authentication is properly configured**.

An attacker hosting a page on a same-site origin (e.g., a sibling subdomain, or another service on localhost) can initiate a WebSocket connection to the exec endpoint that carries the victim's valid JWT cookie, gaining interactive shell access in any container the victim is authorized to access.

## Root cause

**1. CheckOrigin bypassed (`internal/web/terminal.go:15-21`)**

```go var upgrader = websocket.Upgrader{ ReadBufferSize: 1024, WriteBufferSize: 1024, CheckOrigin: func(r *http.Request) bool { return true }, } ```

The gorilla/websocket default CheckOrigin rejects cross-origin requests. Overriding it to return `true` removes the only server-side defense against CSWSH.

**2. JWT cookie with SameSite=Lax (`internal/web/auth.go:20-27`)**

```go http.SetCookie(w, &http.Cookie{ Name: "jwt", Value: token, HttpOnly: true, Path: "/", SameSite: http.SameSiteLaxMode, Expires: expires, }) ```

`SameSite` operates at the **site** level (eTLD+1), not the origin level. A page on `evil.example.com` can make a WebSocket request to `dozzle.example.com` and the browser will attach the JWT c…