CarrierWave content-Type allowlist bypass vulnerability which possibly leads to XSS remained
Published: March 25, 2024
SECURITY IDENTIFIERS
- CVE: CVE-2024-29034 (NVD)
- GHSA: GHSA-vfmv-jfc5-pjjw
- Vendor Advisory: https://github.com/carrierwaveuploader/carrierwave/security/advisories/GHSA-vfmv-jfc5-pjjw
GEM
SEVERITY
CVSS v3.x: 6.8 (Medium)
PATCHED VERSIONS
~> 2.2.6
>= 3.0.7
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
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