CVE Catalog

CVE-2026-46644

MediumCVSS 6.9
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.39%

32th percentile - higher than 32% of all known CVEs

Summary

A vulnerability in symfony/polyfill-intl-idn (versions 1.17.1 through 1.38.1) allows accepting xn-- labels with empty or ASCII-only payload, violating UTS #46 requirements. This can cause different domain names to be considered equal.

Risk Assessment

Risk of blacklist bypass, inconsistent URL parsing, and server-side request forgery (SSRF) in applications using this polyfill for hostname canonicalization or comparison.

Recommendation

Immediately update symfony/polyfill-intl-idn to version 1.38.1 or later, which contains the fix.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS