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CVE-2026-74766VulnerabilityPublished Updated

Libnet idn encode perl: Net::IDN::Punycode versions from 2.301 before 2.590 for Perl allow a heap use-after-free via a

Affects libnet-idn-encode-perlSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-74766· High 8.4

Not known to be exploited · CVSS 8.4 High · fixed in 2.590 : patch libnet-idn-encode-perl soon.

Data as of 5 Nov 2026, 00:01 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 4 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10libnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=stonkingOther threatsAffected
  • =2.500-5build1
  • =2.500-5build2
Fixed in–
Ubuntu 26.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=resoluteOther threatsAffected
  • =2.500-5build1
Fixed in–
Ubuntu 24.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=nobleOther threatsAffected
  • 2.500-3 – 2.500-5
4 affected builds
Fixed in–
Ubuntu 22.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=jammyOther threatsAffected
  • =2.500-1build2
  • =2.500-2
  • =2.500-2build1
Fixed in–
Ubuntu 20.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=focalOther threatsAffected
  • =2.500-1
  • =2.500-1build1
Fixed in–
Ubuntu 18.04 LTSlibnet-idn-encode-perlpkg:deb/ubuntu/libnet-idn-encode-perl?arch=source&distro=bionicOther threatsAffected
  • =2.400-1build1
Fixed in–

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

AI-suggested

A fixed version is available starting from 2.590. Users should upgrade to version 2.590 or later to remediate this vulnerability. No other mitigation or workaround is indicated.

Description

Net::IDN::Punycode versions from 2.301 before 2.590 for Perl contain a heap use-after-free vulnerability in the XS backend's decode_punycode function. This flaw occurs when decoding punycode labels with code points above U+FFFF, which causes the output buffer to reallocate improperly, leading to use of freed memory. The vulnerability allows reading and writing of freed heap memory, potentially resulting in high impact on confidentiality, integrity, and availability.

References

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