Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b6515
- https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7
- https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes
- http://www.openwall.com/lists/oss-security/2026/09/22/16
FAQ
What is CVE-2026-87081?
CVE-2026-87081 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2026-87081?
CVE-2026-87081 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-87081?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.