Vulnerability · Published Sep 22, 2026 · Assigned by CPANSec
CVE-2026-93712Dancer2 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
High 7.5
In plain English
A high-severity path traversal in Dancer2. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libdancer2-perl | no fix listed | DEBIAN-CVE-2026-93712 |
| Debian:13 | libdancer2-perl | no fix listed | DEBIAN-CVE-2026-93712 |
| Debian:14 | libdancer2-perl | 2.2.2-1 | DEBIAN-CVE-2026-93712 |
| Ubuntu:22.04:LTS | libdancer2-perl | no fix listed | UBUNTU-CVE-2026-93712 |
| Ubuntu:24.04:LTS | libdancer2-perl | no fix listed | UBUNTU-CVE-2026-93712 |
| Ubuntu:26.04:LTS | libdancer2-perl | no fix listed | UBUNTU-CVE-2026-93712 |
| Ubuntu:26.10 | libdancer2-perl | no fix listed | UBUNTU-CVE-2026-93712 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Dancer2 | 2.1.0 – before 2.2.0 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
- https://github.com/PerlDancer/Dancer2/security/advisories/GHSA-6xw8-v24c-m783 vendor-advisory
- https://github.com/PerlDancer/Dancer2/commit/2446a09ffb83fef71cc75c327bd6e4b1f007b885.patch patch
- https://metacpan.org/release/CROMEDOME/Dancer2-2.2.0/changes release-notes
- http://www.openwall.com/lists/oss-security/2026/09/22/4