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
Attackers can inject arbitrary HTTP headers and split responses by exploiting missing CR/LF stripping in Dancer2 header names.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93711?
CVE-2026-93711 is a medium-severity vulnerability, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-113
Which versions are affected by CVE-2026-93711?
How do I fix CVE-2026-93711?
Upgrade to a fixed version.
Is CVE-2026-93711 being exploited?
There is no known exploitation of CVE-2026-93711 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-93711, GHSA-vp8p-vxw7-c877, UBUNTU-CVE-2026-93711.