GHSA-4vq8-7jfc-9cvp
LOWMoby firewalld reload removes bridge network isolation
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/docker/docker🐹github.com/docker/dockerReal-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
Moby is an open source container framework developed by Docker Inc. that is distributed as Docker Engine, Mirantis Container Runtime, and various other downstream projects/products. The Moby daemon component (dockerd), which is developed as moby/moby is commonly referred to as Docker, or Docker Engine.
Firewalld is a daemon used by some Linux distributions to provide a dynamically managed firewall. When Firewalld is running, Docker uses its iptables backend to create rules, including rules to isolate containers in one bridge network from containers in other bridge networks.
Impact
The iptables rules created by Docker are removed when firewalld is reloaded using, for example "firewall-cmd --reload", "killall -HUP firewalld", or "systemctl reload firewalld".
When that happens, Docker must re-create the rules. However, in affected versions of Docker, the iptables rules that isolate containers in different bridge networks from each other are not re-created.
Once these rules have been removed, containers have access to any port, on any container, in any non-internal bridge network, running on the Docker host.
Containers running in networks created with --internal or equivalent have no access to other networks. Containers that are only connected to these networks remain isolated after a firewalld reload.
Where Docker Engine is not running in the host's network namespace, it is unaffected. Including, for example, Rootless Mode, and Docker Desktop.
Patches
Moby releases 28.0.0 and newer are not affected. A fix is available in moby release 25.0.13.
Workarounds
After reloading firewalld, either:
- Restart the docker daemon,
- Re-create bridge networks, or
- Use rootless mode.
References
https://firewalld.org/ https://firewalld.org/documentation/howto/reload-firewalld.html
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/docker/docker | all versions | 25.0.13 |
| 🐹Go | github.com/docker/docker | ≥ 26.0.0-rc1&&< 28.0.0 | 28.0.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/docker/docker. 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/docker/docker to 25.0.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4vq8-7jfc-9cvp 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-4vq8-7jfc-9cvp 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-4vq8-7jfc-9cvp. 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-4vq8-7jfc-9cvp in your dependencies?
O3 detects GHSA-4vq8-7jfc-9cvp across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.