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CVE-2026-46644

CVE-2026-46644 · symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload decodes to ASCII-only: insecure equivalence

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.9 · Medium · EPSS 0.5% · Fix available

Published
Updated

Stack: system · php

Affected products and versions

  • polyfill

    Versions
    • >= 1.17.1, < 1.38.1: Affected

    No fix published

  • polyfill-intl-idn

    Versions
    • >= 1.17.1, < 1.38.1: Affected

    No fix published

  • php-symfony-polyfill Debian:12

    Versions
    • 1.27.0-2
    • 1.28.0-1
    • 1.29.0-1
    • 1.29.0-2
    • 1.29.0-3
    • 1.30.0-1
    • 1.31.0-1
    • 1.31.0-2
    • 1.31.0-3
    • 1.31.0-4
    • 1.31.0-5
    • 1.32.0-1
    • 1.33.0-1
    • 1.33.0-2
    • 1.33.0-3
    • 1.33.0-4
    • 1.33.0-5
    • 1.33.0-6
    • 1.36.0-1
    • 1.37.0-1
    • 1.38.1-1
    • 1.40.0-1
    • 1.40.0-2
    • 1.41.0-1
    • 1.41.0-2
    • 1.42.0-1
    • 1.42.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Debian:14

    Versions
    • 1.1.0-1
    • 1.1.1-1
    • 1.17.0-1
    • 1.17.0-2
    • 1.17.1-1
    • 1.18.0-1
    • 1.18.1-1
    • 1.2.0-1
    • 1.21.0-1
    • 1.21.0-2
    • 1.22.0-1
    • 1.22.0-1~exp1
    • 1.22.0-2
    • 1.22.0-3
    • 1.22.1-1
    • 1.23.0-1
    • 1.23.1-1
    • 1.23.1-2
    • 1.24.0-1
    • 1.25.0-1
    • 1.25.0-2
    • 1.25.0-3
    • 1.25.0-4
    • 1.26.0-1
    • 1.26.0-2
    • 1.26.0-3
    • 1.27.0-1
    • 1.27.0-1~new
    • 1.27.0-2
    • 1.28.0-1
    • 1.29.0-1
    • 1.29.0-2
    • 1.29.0-3
    • 1.30.0-1
    • 1.31.0-1
    • 1.31.0-2
    • 1.31.0-3
    • 1.31.0-4
    • 1.31.0-5
    • 1.32.0-1
    • 1.33.0-1
    • 1.33.0-2
    • 1.33.0-3
    • 1.33.0-4
    • 1.33.0-5
    • 1.33.0-6
    • 1.36.0-1
    • 1.37.0-1
    • 1.5.0-1
    • 1.6.0-1
    • 1.6.0-2
    • 1.7.0-1
    • 1.8.0-1
    • 1.9.0-1
    Affected ranges
    • ECOSYSTEM: < 1.38.1-1

    Update to 1.38.1-1

  • symfony/polyfill Packagist

    Versions
    • v1.17.1
    • v1.18.0
    • v1.18.1
    • v1.19.0
    • v1.20.0
    • v1.22.0
    • v1.22.1
    • v1.23.0
    • v1.23.1
    • v1.24.0
    • v1.25.0
    • v1.26.0
    • v1.27.0
    • v1.28.0
    • v1.29.0
    • v1.30.0
    • v1.31.0
    • v1.32.0
    • v1.33.0
    • v1.34.0
    • v1.35.0
    • v1.36.0
    • v1.37.0
    • v1.38.0
    Affected ranges
    • ECOSYSTEM: ≥ 1.17.1, < 1.38.1

    Update to 1.38.1

  • symfony/polyfill-intl-idn Packagist

    Versions
    • v1.17.1
    • v1.18.0
    • v1.18.1
    • v1.19.0
    • v1.20.0
    • v1.22.0
    • v1.22.1
    • v1.23.0
    • v1.24.0
    • v1.25.0
    • v1.26.0
    • v1.27.0
    • v1.28.0
    • v1.29.0
    • v1.30.0
    • v1.31.0
    • v1.32.0
    • v1.33.0
    • v1.34.0
    • v1.35.0
    • v1.36.0
    • v1.37.0
    Affected ranges
    • ECOSYSTEM: ≥ 1.17.1, < 1.38.1

    Update to 1.38.1

  • php-symfony-polyfill Ubuntu:18.04:LTS

    Versions
    • 1.2.0-1ubuntu1
    • 1.6.0-1
    • 1.6.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Ubuntu:22.04:LTS

    Versions
    • 1.22.1-1
    • 1.23.1-1
    • 1.24.0-1ubuntu1
    • 1.24.0-1ubuntu2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Ubuntu:24.04:LTS

    Versions
    • 1.27.0-2
    • 1.28.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Ubuntu:25.10

    Versions
    • 1.31.0-4ubuntu1
    • 1.31.0-5ubuntu1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Ubuntu:26.10

    Versions
    • 1.33.0-6ubuntu1
    • 1.37.0-1ubuntu1
    • 1.40.0-2
    • 1.41.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • php-symfony-polyfill Ubuntu:26.04:LTS

    Versions
    • 1.31.0-5ubuntu1
    • 1.33.0-4ubuntu1
    • 1.33.0-5ubuntu1
    • 1.33.0-6ubuntu1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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