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: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

Vendor Solution

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

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 22 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
References
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 22 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

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

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-09-22T17:07:31.325Z

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

Link: CVE-2026-87081

cve-icon Vulnrichment

Updated: 2026-09-22T17:07:31.325Z

cve-icon NVD

Status : Deferred

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

Modified: 2026-09-22T19:07:00.983

Link: CVE-2026-87081

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-22T18:00:17Z

Weaknesses
  • CWE-407

    Inefficient Algorithmic Complexity