CVE-2026-87081

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.

Overview

State: PUBLISHED
Assigner (CNA): CPANSec
CVSS severity: —
CVSS score: —
CVSS vector: —
Effective score: 7.5 / 10 HIGH source: NVD
CWE(s): CWE-407
Reserved: 2026-09-08
Published: 2026-09-22 07:25 UTC
Last updated: 2026-09-22 17:07 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/87xxx/CVE-2026-87081.json
Linked Threat: 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

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-22 08:16:40 UTC
NVD last modified: 2026-09-22 19:07:00 UTC
NVD CVSS v3.1: 7.5 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploitability subscore: 3.9 / 10
Impact subscore: 3.6 / 10
EPSS score: 0.0015 (probability of exploitation in next 30 days)
EPSS percentile: 5.04% vs all CVEs — higher = more likely to be exploited, as of 2026-09-22

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84294
Assigner: CPANSec
Published: Sep 22, 2026, 7:25:22 AM
Updated: Sep 22, 2026, 5:07:31 PM
EUVD base score (CVSS 3.1): 7.5 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EUVD-reported EPSS: 0.1600
Aliases: GHSA-653x-rhrr-h9h8

ENISA 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.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
—	—	`0` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (4)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

http://www.openwall.com/lists/oss-security/2026/09/22/16 af854a3a-2127-422b-91ae-364da2661108
https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e

Remediations (14)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-87081 | Vulnerability Database | Aqua Security

web:avd.aquasec.com

CVE-2026-87081 Vulnerability, Severity 0 N/A, Inefficient Algorithmic Complexity

2026-09-23 15:42 UTC
Microsoft and Adobe Patch Tuesday, August 2026 Security Update Review

web:blog.qualys.com

The August 2026 Microsoft Patch Tuesday release delivers security fixes for vulnerabilities affecting a wide range of Microsoft products and services.

2026-09-23 15:42 UTC
August 2026 cumulative update - .NET Framework | Microsoft Learn

web:learn.microsoft.com

This update installs the complete .NET Framework 3.5 product for Windows 11, version 26H1 (build version 28000) and newer. Unlike traditional cumulative updates that patch individual components, this update delivers the full .NET Framework 3.5 product as a standalone installer. It replaces any previously installed version.

2026-09-23 15:42 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-23 15:42 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-23 15:42 UTC
August 2026 CVE Advisory Notification - Security

web:support.servicenow.com

Due to additional analysis provided by the security researcher who discovered CVE - 2026 -6876, we have upgraded the severity rating of CVE - 2026 -6876 from High to Critical. This change affects only the severity

2026-09-23 15:42 UTC
CVE-2026-87081 | Ubuntu

web:ubuntu.com

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 ...

2026-09-23 15:42 UTC
Patch Tuesday September 2026 | Action1

web:www.action1.com

In this issue: September 2026 Patch Tuesday updates from Microsoft, featuring zero-day vulnerabilities and critical security flaws.

2026-09-23 15:42 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-23 15:42 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-23 15:42 UTC
Cisco Identity Services Engine Remote Code Execution and Information ...

web:sec.cloudapps.cisco.com

Multiple vulnerabilities in Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC) could allow a remote attacker to achieve remote code execution or conduct information disclosure attacks on an affected device. For more information about these vulnerabilities, see the Details section of this advisory. Cisco has released software updates that address these ...

2026-09-25 10:07 UTC
Description of the security update for Office 2016: August 11, 2026 ...

web:support.microsoft.com

Be aware that the update in the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home. (See What version of Office am I using?) How to get and install the update Method 1: Microsoft Update This update is available from Microsoft Update. When you turn on ...

2026-09-25 10:07 UTC
What Is CVE Remediation in 2026? - aikido.dev

web:www.aikido.dev

CVE remediation is fixing known flaws in the software you run. Why upgrading often fails, what remediation actually involves, and how backporting fixes it.

2026-09-25 10:07 UTC
June 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft patches 206 vulnerabilities in June 2026 Patch Tuesday, including three publicly disclosed zero-days.

2026-09-25 10:07 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-87081.json.

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