CVE-2026-19953
Public on 2026-08-26
Modified on 2026-08-26
Description
URI::_idna::nameprep only lowercased the label and skipped the Unicode
normalization that RFC 3490/3491 require. As a result, a host that was
not already in NFC encoded to a non-standard A-label that disagrees with
what browsers, curl, Go, Java, and Python compute for the same input --
and that A-label does not round-trip. Code that reads $uri->host for a
security decision (allow/deny lists, SSRF filters, routing, dedup) could
therefore disagree with the host that is actually fetched.
normalization that RFC 3490/3491 require. As a result, a host that was
not already in NFC encoded to a non-standard A-label that disagrees with
what browsers, curl, Go, Java, and Python compute for the same input --
and that A-label does not round-trip. Code that reads $uri->host for a
security decision (allow/deny lists, SSRF filters, routing, dedup) could
therefore disagree with the host that is actually fetched.
CVSS v3 Base Score
See breakdown
Affected Packages
| Platform | Package | Release Date | Advisory | Status |
|---|---|---|---|---|
| Amazon Linux 2 - Core | perl | Not Affected | ||
| Amazon Linux 2023 | perl | Not Affected | ||
| Amazon Linux 2 - Core | perl-URI | Pending Fix | ||
| Amazon Linux 2023 | perl-URI | Pending Fix |
CVSS Scores
| Score Type | Score | Vector | |
|---|---|---|---|
| Amazon Linux | CVSSv3 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |