---
id: CVE-2026-93711
title: >-
  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
summary: >-
  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 se…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-113
product: Dancer2
affected:
  - Dancer2 < 2.2.0
published: '2026-09-22'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T20:17:12.423'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93711'
references:
  - url: >-
      https://github.com/PerlDancer/Dancer2/commit/ff89ac12af7b8899812a79e9924dfea7a5d9833b.patch
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'https://github.com/PerlDancer/Dancer2/issues/1822'
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes'
    label: 9b29abf9-4ab0-4765-b253-1875cd9b441e
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/22/3'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
epss: 0.00372
epssPercentile: 0.28473
ingestedAt: '2026-09-22T00:55:54.014Z'
---

## Overview

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

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.