CPANSA-Dancer2-2026-93711: Dancer2 vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-09-22T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-09-22T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 6.5 | Severity | Medium |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability 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.
Vulnerabilities
CVE-2026-93711
Vulnerability DescriptionDancer2 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.
| Weakness | CWE-113 : Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Dancer2 less than 2.2.0 |
|
Fixed
- Dancer2 greater than or equal 2.2.0
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-Dancer2-2026-93711 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-dancer2-2026-93711.json - https://github.com/PerlDancer/Dancer2/commit/ff89ac12af7b8899812a79e9924dfea7a5d9833b.patch external
https://github.com/PerlDancer/Dancer2/commit/ff89ac12af7b8899812a79e9924dfea7a5d9833b.patch - https://github.com/PerlDancer/Dancer2/issues/1822 external
https://github.com/PerlDancer/Dancer2/issues/1822 - https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes external
https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes - http://www.openwall.com/lists/oss-security/2026/09/22/3 external
http://www.openwall.com/lists/oss-security/2026/09/22/3 - CVE-2026-93711 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2026-93711
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Tue Sep 22 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/