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DEBIAN-CVE-2026-19953

Type: advisorySource: OSV1 source record

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.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-19953

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-19953

liburi-perl

Source reference: /affected/0/package/name

Affected versions
5.17-1

Source reference: /affected/0/versions

5.19-1

Source reference: /affected/0/versions

5.19-2

Source reference: /affected/0/versions

5.21-1

Source reference: /affected/0/versions

5.25-1

Source reference: /affected/0/versions

5.26-1

Source reference: /affected/0/versions

5.27-1

Source reference: /affected/0/versions

5.28-1

Source reference: /affected/0/versions

5.29-1

Source reference: /affected/0/versions

5.30-1

Source reference: /affected/0/versions

5.34-1

Source reference: /affected/0/versions

5.34-2

Source reference: /affected/0/versions

5.35-1

Source reference: /affected/0/versions

5.36-1

Source reference: /affected/0/versions

5.37-1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

liburi-perl

Source reference: /affected/1/package/name

Affected versions
5.30-1

Source reference: /affected/1/versions

5.34-1

Source reference: /affected/1/versions

5.34-2

Source reference: /affected/1/versions

5.35-1

Source reference: /affected/1/versions

5.36-1

Source reference: /affected/1/versions

5.37-1

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

liburi-perl

Source reference: /affected/2/package/name

Affected versions
5.30-1

Source reference: /affected/2/versions

5.34-1

Source reference: /affected/2/versions

5.34-2

Source reference: /affected/2/versions

5.35-1

Source reference: /affected/2/versions

Fixed versions
5.36-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "liburi-perl",
      "purl": "pkg:deb/debian/liburi-perl?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "5.17-1",
      "5.19-1",
      "5.19-2",
      "5.21-1",
      "5.25-1",
      "5.26-1",
      "5.27-1",
      "5.28-1",
      "5.29-1",
      "5.30-1",
      "5.34-1",
      "5.34-2",
      "5.35-1",
      "5.36-1",
      "5.37-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19953.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "liburi-perl",
      "purl": "pkg:deb/debian/liburi-perl?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "5.30-1",
      "5.34-1",
      "5.34-2",
      "5.35-1",
      "5.36-1",
      "5.37-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19953.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "5.36-1"
          }
        ]
      }
    ],
    "package": {
      "name": "liburi-perl",
      "purl": "pkg:deb/debian/liburi-perl?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "5.30-1",
      "5.34-1",
      "5.34-2",
      "5.35-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-19953.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#56192 · Revision 1
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Publisher date
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