Dancer2 versions before 2.2.0 for Perl do not strip CR and LF from response header names in headers_to_array.

The routine removes CR and LF from each header value but not from the name. A name carrying them therefore reaches the PSGI server intact. A server that does not validate keys writes it to the wire, so the bytes after the CRLF arrive as their own header line.

The application has to derive the header name from request data, not just the value.

An attacker who controls that data adds their own headers and splits the response.

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Advisories

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Fixes

Solution

Upgrade to Dancer2 2.2.0 or later.


Workaround

No workaround given by the vendor.

History

Mon, 28 Sep 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Perldancer
Perldancer dancer2
Vendors & Products Perldancer
Perldancer dancer2

Tue, 22 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 22 Sep 2026 03:30:00 +0000

Type Values Removed Values Added
References

Tue, 22 Sep 2026 01:00:00 +0000

Type Values Removed Values Added
Description Dancer2 versions before 2.2.0 for Perl do not strip CR and LF from response header names in headers_to_array. The routine removes CR and LF from each header value but not from the name. A name carrying them therefore reaches the PSGI server intact. A server that does not validate keys writes it to the wire, so the bytes after the CRLF arrive as their own header line. The application has to derive the header name from request data, not just the value. An attacker who controls that data adds their own headers and splits the response.
Title Dancer2 versions before 2.2.0 for Perl do not strip CR and LF from response header names in headers_to_array
Weaknesses CWE-113
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-09-22T19:22:25.244Z

Reserved: 2026-09-18T15:06:50.792Z

Link: CVE-2026-93711

cve-icon Vulnrichment

Updated: 2026-09-22T02:09:47.042Z

cve-icon NVD

Status : Deferred

Published: 2026-09-22T01:16:55.847

Modified: 2026-09-22T20:17:12.423

Link: CVE-2026-93711

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-28T19:48:02Z

Weaknesses