# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-93711, GHSA-vp8p-vxw7-c877, UBUNTU-CVE-2026-93711

## 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 (Improper Neutralization of CRLF Sequences in HTTP Headers)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93711 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-93711 in the wild and no public exploit code.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-93711/ (Markdown: https://insights.sbomify.com/CVE-2026-93711/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93711
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93711
- OSV: https://osv.dev/vulnerability/CVE-2026-93711

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-93711/
Summaries are generated and may contain mistakes; the official description above is the record.