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VulnerabilityPublished

CVE-2026-87079: Net-IDN-Encode (Perl module) · Inefficient Algorithmic Complexity

Affects Net-IDN-Encode (Perl module)Source CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 2.590 soon.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.590
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Upgrade Net-IDN-Encode (Perl module) to 2.590.

Affected software

ProductAffectedFixed in
CPANNet-IDN-Encodepkg:cpan/Net-IDN-EncodeOther threatsAffected
  • <2.590
Fixed in
  • 2.590

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Net::IDN::Punycode version 2.590 and later. Users should upgrade to version 2.590 or newer to resolve this vulnerability.

Description

CVE-2026-87079 is a high-severity vulnerability in Net::IDN::Punycode versions before 2.590 for Perl. It allows an attacker to cause CPU exhaustion due to inefficient quadratic-time processing when decoding long labels in the decode_punycode function. The vulnerability arises because the XS backend scans the UTF-8 buffer from the start for each code point insertion, and the pure-Perl backend similarly incurs quadratic cost when handling UTF-8 flagged input. There is no length bound on labels when converting to Unicode, enabling attackers to supply arbitrarily long labels to trigger this behavior.

References

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