CVE-2026-19954 (CVSS 5.4)

Description

Net::Whois::Raw versions before 2.99044 for Perl ship a pwhois command-line tool that queries WHOIS for the wrong domain for unicode domain names. pwhois encodes each non-ASCII label directly using Net::IDN::Punycode and prepends xn--. Apart from lowercasing ASCII and Cyrillic letters, it skips the IDNA mapping and normalization steps, so a label with other uppercase letters, or not in NFC, encodes to a different A-label than its IDNA form. For example, a label of U+00C9 followed by "cole" encodes to "xn--cole-pka" rather than "xn--cole-9oa". The Net::Whois::Raw library modules are not affected.

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CVSS v3.1 Score

5.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-176 CWE-176

References

Other References

https://github.com/regru/Net-Whois-Raw/issues/34 https://github.com/regru/Net-Whois-Raw/pull/35 https://metacpan.org/release/NALOBIN/Net-Whois-Raw-2.99044/changes https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/view/lib/Net/IDN/Punycode.pm#WARNING https://security.metacpan.org/patches/N/Net-Whois-Raw/2.99043/CVE-2026-19954-r1.patch https://www.rfc-editor.org/rfc/rfc5891#section-5.2 http://www.openwall.com/lists/oss-security/2026/10/05/9

Frequently Asked Questions

What is CVE-2026-19954? +

Net::Whois::Raw versions before 2.99044 for Perl ship a pwhois command-line tool that queries WHOIS for the wrong domain for unicode domain names. pwhois encodes each non-ASCII label directly using Net::IDN::Punycode and prepends xn--. Apart from lowercasing ASCII and Cyrillic letters, it skips the IDNA mapping and normalization steps, so a label with other uppercase letters, or not in NFC, encodes to a different A-label than its IDNA form. For example, a label of U+00C9 followed by "cole" encodes to "xn--cole-pka" rather than "xn--cole-9oa". The Net::Whois::Raw library modules are not affected. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-19954? +

CVE-2026-19954 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-19954? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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