CarrierWave content-Type allowlist bypass vulnerability which possibly leads to XSS remained

Description

Impact

The vulnerability CVE-2023-49090 wasn't fully addressed.

This vulnerability is caused by the fact that when uploading to object storage, including Amazon S3, it is possible to set a Content-Type value that is interpreted by browsers to be different from what's allowed by content_type_allowlist, by providing multiple values separated by commas.

This bypassed value can be used to cause XSS.

Patches

Upgrade to 3.0.7 or 2.2.6.

Workarounds

Use the following monkey patch to let CarrierWave parse the Content-type by using Marcel::MimeType.for.

# For CarrierWave 3.x
CarrierWave::SanitizedFile.class_eval do
  def declared_content_type
    @declared_content_type ||
      if @file.respond_to?(:content_type) && @file.content_type
        Marcel::MimeType.for(declared_type: @file.content_type.to_s.chomp)
      end
  end
end
# For CarrierWave 2.x
CarrierWave::SanitizedFile.class_eval do
  def existing_content_type
    if @file.respond_to?(:content_type) && @file.content_type
      Marcel::MimeType.for(declared_type: @file.content_type.to_s.chomp)
    end
  end
end

References

OWASP - File Upload Cheat Sheet

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2024-03-25 19:40:36 UTC
Updated
2024-03-27 13:00:01 UTC
GitHub reviewed
2024-03-25 19:40:36 UTC
NVD published
2024-03-24

EPSS Score

Score Percentile
0.07% 22.55%

CVSS Scores

Base score Version Severity Vector
6.8 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-436 Interpretation Conflict

Credits

  • a-zara-n (analyst)

Affected packages (2)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
rubygems carrierwave >= 3.0.0, < 3.0.7 3.0.7
rubygems carrierwave < 2.2.6 2.2.6

References

cvelogic Threat Intelligence