CVE-2026-46643 Snappy: Binary path is never shell-escaped due to an inverted is_executable check

Snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page. Prior to version 1.7.1, on POSIX, escapeshellarg‘/usr/bin/wkhtmltopdf’ returns the literal string ‘/usr/bin/wkhtmltopdf’ with the single-quote characters included. isexecutable then looks for a file...