CVE-2021-21305
HIGHCVE-2021-21305 is a high-severity (CVSS 8.8) CWE-74 vulnerability in carrierwave. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2021-21305 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Code Injection vulnerability in CarrierWave::RMagick
Blast Radius
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
CarrierWave is an open-source RubyGem which provides a simple and flexible way to upload files from Ruby applications. In CarrierWave before versions 1.3.2 and 2.1.1, there is a code injection vulnerability. The "#manipulate!" method inappropriately evals the content of mutation option(:read/:write), allowing attackers to craft a string that can be executed as a Ruby code. If an application developer supplies untrusted inputs to the option, it will lead to remote code execution(RCE). This is fixed in versions 1.3.2 and 2.1.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | carrierwave | all versions | 1.3.2 |
| 💎RubyGems | carrierwave | ≥ 2.0.0&&< 2.1.1 | 2.1.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for carrierwave. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update carrierwave to 1.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21305 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 pinpoints whether CVE-2021-21305 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2021-21305. 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-2021-21305 in your dependencies?
O3 detects CVE-2021-21305 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.