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 revision 33 requirement that decoded ACE labels contain at least one non-ASCII code point. Originally unequal domain names can be regarded as equal, which can lead to blacklist bypassing, inconsistent URL parsing, and server-side request forgery in applications using the polyfill to canonicalise or compare hostnames. This issue is fixed in version 1.38.1.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-1289"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46644.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "1.17.1"
},
{
"fixed": "1.38.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "1be936e2491ccebe152bd736dfc91eb1422c8bec"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v1.38.1",
"range": [
{
"fixed": "09e53d15109121636a416310ea0d510bd292c463"
}
],
"source": "REFERENCES_TAG"
}
]
}