Inappropriate Encoding for Output Context Affecting perl-URI package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.23% (13th percentile)

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  • Snyk IDSNYK-CENTOS10-PERLURI-20412758
  • published3 Oct 2026
  • disclosed31 Aug 2026

Introduced: 31 Aug 2026

CVE-2026-19953  (opens in a new tab)
CWE-838  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 perl-URI.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perl-URI package and not the perl-URI package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

URI versions before 5.36 for Perl encode non-NFC host names to non-standard punycode labels via missing normalization in nameprep.

nameprep lowercases each host label but performs no Unicode normalization. IDNA requires a label to be normalized to Form C before it is encoded (RFC 5891), so a label that is not already in NFC is encoded to a different A-label than its normalized form. A label built from the precomposed Devanagari sequence U+0958 U+093E encodes to xn--72b5c without normalization but to xn--11b2fg after NFC normalization, and xn--72b5c does not round-trip back to the original label.

Any caller that reads host() from a URI built from untrusted input and uses it for a security decision (an allow or deny list, an SSRF filter, deduplication, a cache key) sees the non-standard label, while a client that fetches the same URL resolves the NFC form, so the check and the fetch can disagree about the host.

CVSS Base Scores

version 3.1