🛡️ RUSTSEC-2026-0257 — webbrowser

Unix BROWSER handling allows browser argument injection

On Unix platforms handled by src/unix.rs, affected versions substitute the

caller-supplied URL into the BROWSER environment-variable template before

tokenizing the resulting string with split_ascii_whitespace(). If an

application passes an attacker-controlled non-HTTP(S) URL whose parsed form

retains spaces and the effective BROWSER template contains %s, text that

should remain within one URL argument becomes additional browser arguments.

The issue was reproduced with Chromium by injecting

--remote-debugging-port, which exposed a local DevTools endpoint, and

--proxy-server, which redirected browser traffic through an

attacker-controlled proxy. The available arguments and resulting impact depend

on the browser launched by the affected application.

Version 1.2.2 fixes the issue by tokenizing the BROWSER template before

substituting the URL, preserving the URL as part of a single argument. Users

should upgrade to version 1.2.2 or later. Applications that only need HTTP(S)

URLs can also enable the crate's hardened feature as defense in depth.

This issue was reported by

[@dywzju09-blip](https://github.com/dywzju09-blip).