---
title: "CVE-2026-87081: Net::IDN::UTS46 - Denial of Service"
description: "Net::IDN::UTS46 < 2.590 for Perl contains a denial of service caused by quadratic punycode encoding of an overlong label before length check in to_ascii, letting attackers exhaust CPU resources, exploit requires sending crafted input with many distinct non-ASCII characters."
url: https://panop.io/threat-heartbeat/CVE-2026-87081/
---

# CVE-2026-87081 Net::IDN::UTS46 - Denial of Service

Net::IDN::UTS46 < 2.590 for Perl contains a denial of service caused by quadratic punycode encoding of an overlong label before length check in to\_ascii, letting attackers exhaust CPU resources, exploit requires sending crafted input with many distinct non-ASCII characters.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.38% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-87081)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

22 September 2026

Updated

15 October 2026

Weakness

[CWE-407](https://cwe.mitre.org/data/definitions/407.html)

## Vendor fix

Update to version 2.590 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-87081](https://nvd.nist.gov/vuln/detail/CVE-2026-87081)
- [https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch](https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch)
- [https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch](https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch)
- [https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes](https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes)
- [http://www.openwall.com/lists/oss-security/2026/09/22/16](http://www.openwall.com/lists/oss-security/2026/09/22/16)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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