CVE-2025-27221
LOWCVE-2025-27221 is a low-severity (CVSS 3.2) CWE-212 vulnerability in uri. O3 Security confirms whether CVE-2025-27221 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
URI allows for userinfo Leakage in URI#join, URI#merge, and URI#+
Real-World Exposure
uri💎uri💎uri💎uriReal-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
In the URI gem before 1.0.3 for Ruby, the URI handling methods (URI.join, URI#merge, URI#+) have an inadvertent leakage of authentication credentials because userinfo is retained even after changing the host.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | uri | all versions | 0.11.3 |
| 💎RubyGems | uri | ≥ 0.12.0&&< 0.12.4 | 0.12.4 |
| 💎RubyGems | uri | ≥ 0.13.0&&< 0.13.2 | 0.13.2 |
| 💎RubyGems | uri | ≥ 1.0.0&&< 1.0.3 | 1.0.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for uri. 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 uri to 0.11.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27221 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-2025-27221 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-2025-27221. 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-2025-27221 in your dependencies?
O3 detects CVE-2025-27221 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.