---
title: "CVE-2016-15059: Net::IDN::Punycode - Buffer Overflow"
description: "Net::IDN::Punycode < 2.301 for Perl contains a heap buffer overflow caused by unchecked writes past the output buffer in encode_punycode XS backend, letting attackers corrupt heap memory remotely, exploit requires crafted input string."
url: https://panop.io/threat-heartbeat/CVE-2016-15059/
---

# CVE-2016-15059 Net::IDN::Punycode - Buffer Overflow

Net::IDN::Punycode < 2.301 for Perl contains a heap buffer overflow caused by unchecked writes past the output buffer in encode\_punycode XS backend, letting attackers corrupt heap memory remotely, exploit requires crafted input string.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.42% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2016-15059)

## Details

Type

Buffer Overflow

Impact

Denial Of Service, Remote Code Execution

CVSS vector

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

Published

22 September 2026

Updated

15 October 2026

Weakness

[CWE-122](https://cwe.mitre.org/data/definitions/122.html)

## Vendor fix

Update to version 2.301 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-2016-15059](https://nvd.nist.gov/vuln/detail/CVE-2016-15059)
- [https://github.com/robrwo/Net-IDN-Encode/commit/9a3ba07f15d22c0347eefee9625b012cbc803657.patch](https://github.com/robrwo/Net-IDN-Encode/commit/9a3ba07f15d22c0347eefee9625b012cbc803657.patch)
- [https://metacpan.org/release/CFAERBER/Net-IDN-Encode-2.301/changes](https://metacpan.org/release/CFAERBER/Net-IDN-Encode-2.301/changes)
- [https://rt.cpan.org/Ticket/Display.html?id=118924](https://rt.cpan.org/Ticket/Display.html?id=118924)
- [http://www.openwall.com/lists/oss-security/2026/09/22/10](http://www.openwall.com/lists/oss-security/2026/09/22/10)

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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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