CVE-2026-87080 Affecting libnet-idn-encode-perl package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-LIBNETIDNENCODEPERL-20044733
- published22 Sept 2026
- disclosed22 Sept 2026
Introduced: 22 Sep 2026
NewCVE-2026-87080 (opens in a new tab)How to fix?
There is no fixed version for Debian:unstable libnet-idn-encode-perl.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libnet-idn-encode-perl package and not the libnet-idn-encode-perl package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
Net::IDN::Punycode::PP versions before 2.590 for Perl decode a truncated label to a name containing a character it never encoded in decode_punycode.
The pure-Perl decoder reads one digit at a time with four-argument substr and tests the result with defined to detect the end of the input. substr on an exhausted string returns the empty string rather than undef, so decoding continues past the end. The empty string converts to a digit value below the range, reducing the accumulator, and the decoder derives one extra code point and its position from it. The result is deterministic. The XS backend rejects the same label.
Net::IDN::Punycode uses this backend wherever the XS does not build.
The two backends disagree about what such a label means, so a sender can pick a label that one installation resolves to a name and another rejects.