Skip to content

Content-Type allowlist bypass vulnerability, possibly leading to XSS

Moderate
mshibuya published GHSA-gxhx-g4fq-49hj Nov 29, 2023

Package

bundler carrierwave (RubyGems)

Affected versions

< 3.0.5 and < 2.2.5

Patched versions

3.0.5, 2.2.5

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

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N

CVE ID

CVE-2023-49090

Weaknesses

No CWEs

Credits