CVE-2026-87081

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch
https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch
https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes
http://www.openwall.com/lists/oss-security/2026/09/22/16

Configurations

No configuration.

History

22 Sep 2026, 18:17

Type	Values Removed	Values Added
References		() http://www.openwall.com/lists/oss-security/2026/09/22/16 -

22 Sep 2026, 16:18

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5

22 Sep 2026, 08:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-22 08:16

Updated : 2026-09-22 19:07

NVD link : CVE-2026-87081

Mitre link : CVE-2026-87081

CVE.ORG link : CVE-2026-87081

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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