GHSA-jv3w-x3r3-g6rm
MEDIUMCNA Plugins Portmap nftables backend can intercept non-local traffic
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.
Blast Radius
github.com/containernetworking/pluginsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Background
The CNI portmap plugin allows containers to emulate opening a host port, forwarding that traffic to the container. For example, if a host has the IP 198.51.100.42, a container may request that all packets to 198.51.100.42:53 be forwarded to the container's network.
Vulnerability
When the portmap plugin is configured with the nftables backend, it inadvertently forwards all traffic with the same destination port as the host port, ignoring the destination IP. This includes traffic not intended for the node itself, i.e. traffic to containers hosted on the node.
In the given example above, traffic destined to port 53 but for a separate container would still be captured and forwarded, even though it was not destined for the host.
Impact
Containers (i.e. kubernetes pods) that request HostPort forwarding can intercept all traffic destined for that port. This requires that the portmap plugin be explicitly configured to use the nftables backend. (The iptables backend is the default.)
Patches
This is fixed as of CNI plugins v1.9.0
Workarounds
Configure the portmap plugin to use the iptables backend. It does not have this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/containernetworking/plugins | ≥ 1.6.0&&< 1.9.0 | 1.9.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/containernetworking/plugins. 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 github.com/containernetworking/plugins to 1.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jv3w-x3r3-g6rm 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-jv3w-x3r3-g6rm 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-jv3w-x3r3-g6rm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-jv3w-x3r3-g6rm in your dependencies?
O3 detects GHSA-jv3w-x3r3-g6rm across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.