CVE-2021-33473 is a critical-severity (CVSS 9.1) CWE-88 vulnerability in dragonfly. A fix is available for dragonfly — see the affected versions and patch details below.
Arbitrary file write in dragonfly
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
dragonflyReal-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
An argument injection vulnerability in Dragonfly Ruby Gem v1.3.0 allows attackers to read and write arbitrary files when the verify_url option is disabled. This vulnerability is exploited via a crafted URL.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | dragonfly | all versions | 1.4.0bundle update dragonfly --conservative |
Affected Products
dragonflydragonfly_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for dragonfly, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update dragonfly to 1.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-33473 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.
Frequently Asked Questions
Is CVE-2021-33473 in your dependencies?
Find it across RubyGems, including transitive dependencies.