Incorrect Comparison Affecting symfony/polyfill-intl-idn package, versions >=1.17.1, <1.38.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-SYMFONYPOLYFILLINTLIDN-16881598
- published27 May 2026
- disclosed26 May 2026
- creditNazy Mad
Introduced: 26 May 2026
CVE-2026-46644 (opens in a new tab)How to fix?
Upgrade symfony/polyfill-intl-idn to version 1.38.1 or higher.
Overview
Affected versions of this package are vulnerable to Incorrect Comparison in the process() function in Idn.php, which does not necessarily treat xn-- labeled input as punycode, if it contains only ASCII. This case was overlooked in the specification until UTS #46 revision 33, when it was enforced that an error must be returned. An attacker can exploit the flawed comparison to bypass domain blocklists and perform SSRF, by supplying a malicious hostname whose punycode representation exactly matches a legitimate internal resource.