# CVE-2026-46644

## Summary

- **CVE ID:** CVE-2026-46644
- **Severity:** MEDIUM
- **CVSS Score:** 6.9 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N)
- **CWE:** CWE-1289
- **Published:** Jul 14, 2026
- **Last Modified:** Jul 15, 2026

## Description

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.

## Affected Products

- symfony — polyfill (>= 1.17.1, < 1.38.1)
- symfony — polyfill-intl-idn (>= 1.17.1, < 1.38.1)

## References

- [CNA](https://github.com/symfony/polyfill/security/advisories/GHSA-2xf4-cg6j-vhgq)
- [CNA](https://github.com/symfony/polyfill/commit/1be936e2491ccebe152bd736dfc91eb1422c8bec)
- [CNA](https://github.com/symfony/polyfill/releases/tag/v1.38.1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.54%
- **EPSS Percentile:** 43.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._