CVE-2025-25186 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in net-imap. O3 Security confirms whether CVE-2025-25186 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Net::IMAP vulnerable to possible DoS by memory exhaustion
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-2025-25186 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 356,453 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
net-imap💎net-imap💎net-imapReal-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
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Starting in version 0.3.2 and prior to versions 0.3.8, 0.4.19, and 0.5.6, there is a possibility for denial of service by memory exhaustion in net-imap's response parser. At any time while the client is connected, a malicious server can send can send highly compressed uid-set data which is automatically read by the client's receiver thread. The response parser uses Range#to_a to convert the uid-set data into arrays of integers, with no limitation on the expanded size of the ranges. Versions 0.3.8, 0.4.19, 0.5.6, and higher fix this issue. Additional details for proper configuration of fixed versions and backward compatibility are available in the GitHub Security Advisory.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | net-imap | ≥ 0.3.2&&< 0.3.8 | 0.3.8 |
| 💎RubyGems | net-imap | ≥ 0.4.0&&< 0.4.19 | 0.4.19 |
| 💎RubyGems | net-imap | ≥ 0.5.0&&< 0.5.6 | 0.5.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for net-imap. 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 net-imap to 0.3.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-25186 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-2025-25186 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-2025-25186. 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-2025-25186 in your dependencies?
O3 detects CVE-2025-25186 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.