CGA-wmxr-wv5g-j7gj

Summary

CarrierWave Content-Type allowlist bypass vulnerability, possibly leading to XSS

Description

Impact

CarrierWave::Uploader::ContentTypeAllowlist has a Content-Type allowlist bypass vulnerability, possibly leading to XSS.

The validation in allowlisted_content_type? determines Content-Type permissions by performing a partial match. If the content_type argument of allowlisted_content_type? is passed a value crafted by the attacker, Content-Types not included in the content_type_allowlist will be allowed.

In addition, by setting the Content-Type configured by the attacker at the time of file delivery, it is possible to cause XSS on the user's browser when the uploaded file is opened.

Patches

Upgrade to 3.0.5 or 2.2.5.

Workarounds

When validating with allowlisted_content_type? in CarrierWave::Uploader::ContentTypeAllowlist , forward match(\A) the Content-Type set in content_type_allowlist, preventing unintentional permission of text/html;image/png when you want to allow only image/png in content_type_allowlist.

References

OWASP - File Upload Cheat Sheet