CVE-2026-46644

Symfony Polyfill backports PHP features and provides compatibility layers for extensions and functions. From 1.17.1 until 1.38.1, symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload is empty or decodes to ASCII-only code points because Idn::process does not enforce the UTS 46...

GHSA-2XF4-CG6J-VHGQ symfony/polyfill-intl-idn: xn-- labels with ASCII-only Punycode payloads are treated as equivalent to their decoded form

Description symfony/polyfill-intl-idn provides a userland implementation of idntoutf8 and idntoascii for runtimes that lack the intl extension. Its Idn::process method decodes labels prefixed with xn-- using Punycode but never enforces the validity criterion added in UTS 46 revision 33 Section 4...