CVE-2017-0904 is a high-severity (CVSS 8.1) CWE-242 vulnerability in private_address_check. A fix is available for private_address_check — see the affected versions and patch details below.
private_address_check vulnerable to bypass of Resolv.getaddresses method
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2017-0904 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 388,997 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
private_address_checkReal-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
The private_address_check ruby gem before 0.4.0 is vulnerable to a bypass due to use of Ruby's Resolv.getaddresses method, which is OS-dependent and should not be relied upon for security measures, such as when used to blacklist private network addresses to prevent server-side request forgery.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | private_address_check | all versions | 0.4.0bundle update private_address_check --conservative |
Affected Products
private address checkprivate_address_check_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for private_address_check, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update private_address_check to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-0904 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.
Frequently Asked Questions
Is CVE-2017-0904 in your dependencies?
Find it across RubyGems, including transitive dependencies.