PerlDancer Dancer2 up to 2.1.x Header Name headers_to_array crlf injection

Summaryinfo

A vulnerability marked as critical has been reported in PerlDancer Dancer2 up to 2.1.x. This issue affects the function headers_to_array of the component Header Name. The manipulation leads to crlf injection. This vulnerability is referenced as CVE-2026-93711. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in PerlDancer Dancer2 up to 2.1.x and classified as critical. This issue affects the function headers_to_array of the component Header Name. The manipulation with an unknown input leads to a crlf injection vulnerability. Using CWE to declare the problem leads to CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-93711 since 09/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.2.0 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• PerlDancer

Name

• Dancer2

Version

• 2.0
• 2.1

Website

• Product: https://github.com/PerlDancer/Dancer2/

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