CVE-2024-29034 is a medium-severity (CVSS 6.8) Cross-site Scripting (XSS) vulnerability in carrierwave. A fix is available for carrierwave — see the affected versions and patch details below.
CarrierWave's Content-Type allowlist bypass vulnerability which possibly leads to XSS remained
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-29034.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-29034 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
carrierwave💎carrierwaveReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
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
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | carrierwave | ≥ 3.0.0&&< 3.0.7 | 3.0.7bundle update carrierwave --conservative |
| 💎RubyGems | carrierwave | all versions | 2.2.6bundle update carrierwave --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for carrierwave, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update carrierwave to 3.0.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-29034 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-29034 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-29034. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-29034 in your dependencies?
O3 Security finds CVE-2024-29034 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.