GHSA-3qp7-7mw8-wx86
HIGHGHSA-3qp7-7mw8-wx86 is a high-severity (CVSS 8.1) CWE-284 vulnerability in io.netty:netty-handler. O3 Security confirms whether GHSA-3qp7-7mw8-wx86 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3qp7-7mw8-wx86.
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
GHSA-3qp7-7mw8-wx86 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 0 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
io.netty:netty-handler☕io.netty:netty-handlerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
An attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions.
Details
io.netty.handler.ipfilter.IpSubnetFilterRule#compareTo(java.net.InetSocketAddress) method performs a bitwise AND between the incoming IP address and the configured networkAddress, instead of the subnetMask.
Impact
Access Control Bypass. Attacker can bypass IpSubnetFilter IPv6 access controls.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.netty:netty-handler | ≥ 4.2.0.Final&&< 4.2.15.Final | 4.2.15.Final |
| ☕Maven | io.netty:netty-handler | all versions | 4.1.135.Final |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-handler. 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 io.netty:netty-handler to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3qp7-7mw8-wx86 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 GHSA-3qp7-7mw8-wx86 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 GHSA-3qp7-7mw8-wx86. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability in netty-handler is rated as Important because a remote attacker can bypass configured IPv6 subnet filtering rules. This flaw, stemming from an incorrect masking operation, could allow unauthorized access to or exposure of services that are intended to be network-restricted within Red Hat products…
Frequently Asked Questions
Is GHSA-3qp7-7mw8-wx86 in your dependencies?
O3 detects GHSA-3qp7-7mw8-wx86 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.