CVE-2026-87081Hinoki check available

CPU exhaustion via post-encoding label length check

Published Sep 22, 2026 · Updated Sep 22, 2026

Denial of service in Net::IDN::UTS46 before 2.590 allows attackers to exhaust CPU by supplying an overlong non-ASCII label. The to_ascii path passed the entire label to encode_punycode before enforcing the 63-byte DNS limit, causing repeated scans of distinct code points. Reachability depends on an application passing attacker-controlled domain or email labels into an ASCII-conversion API; the bounded consequence is CPU exhaustion and service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.38%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in Net::IDN::UTS46 before 2.590 allows attackers to exhaust CPU by supplying an overlong non-ASCII label. The to_ascii path passed the entire label to encode_punycode before enforcing the 63-byte DNS limit, causing repeated scans of distinct code points. Reachability depends on an application passing attacker-controlled domain or email labels into an ASCII-conversion API; the bounded consequence is CPU exhaustion and service interruption.

The record

CVE
CVE-2026-87081
Published
Sep 22, 2026
Updated
Sep 22, 2026
Vendor
Claus Färber
Product
Net-IDN-Encode
Classifications
T1499.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.590

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Claus Färber · Net-IDN-Encodeversion=0 <2.590

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

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No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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