CVE-2026-93711

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

Published Sep 22, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

Upgrade to Dancer2 2.2.0 or later.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Perldancer
Perldancer dancer2
Vendors & Products Perldancer
Perldancer dancer2
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'}

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
Weaknesses

Sources

Status
PUBLISHED
Assigner
CPANSec
Published
Updated
Sep 22, 2026, 7:22 PM
Reserved
Sep 18, 2026, 3:06 PM
Status
Deferred
Published
Sep 22, 2026, 1:16 AM
Modified
Sep 22, 2026, 8:17 PM