Description
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.

to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
Published: 2026-09-22
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

Vendor Solution

Upgrade to Net-IDN-Encode 2.590-TRIAL or later.

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History

Tue, 22 Sep 2026 07:30:00 +0000

Type Values Removed Values Added
Description Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii. to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
Title Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii
Weaknesses CWE-407
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-09-22T07:25:22.090Z

Reserved: 2026-09-08T19:22:20.005Z

Link: CVE-2026-87081

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-22T08:16:40.863

Modified: 2026-09-22T08:16:40.863

Link: CVE-2026-87081

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-22T08:30:17Z

Weaknesses