RUSTSEC-2026-0257: Unix `BROWSER` handling allows browser argument injection
3 affectedOn 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.