CVE Catalog

CVE-2026-87080

CriticalCVSS 9.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.15%

4th percentile - higher than 4% of all known CVEs

Summary

Net::IDN::Punycode::PP versions before 2.590 for Perl decode a truncated label to a name containing a character it never encoded. The XS backend rejects the same label, causing inconsistency between installations.

Risk Assessment

A sender can choose a label that resolves to different names on different installations, potentially bypassing security checks or causing misinterpretation of domain names.

Recommendation

Update Net::IDN::Punycode to version 2.590 or later. Ensure the XS backend is used where possible.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS