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VulnerabilityPublished

CVE-2026-74766: Net-IDN-Encode (Perl module) · Use After Free

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

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Not known to be exploited · CVSS 8.4 High : upgrade to 2.590 soon.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score
8.4High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.590
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 5 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
  • >=2.301 <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

If you cannot patch yet, avoid processing untrusted punycode labels with affected versions or consider disabling the XS backend if feasible.

Description

Net::IDN::Punycode versions from 2.301 up to but not including 2.590 for Perl contain a heap use-after-free vulnerability in the XS backend's decode_punycode function. This flaw arises when decoding certain punycode labels with code points above U+FFFF, causing the output buffer to reallocate without updating all pointers, leading to use of freed memory. This vulnerability allows reading and writing of freed heap memory, potentially resulting in high impact on confidentiality, integrity, and availability.

References

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