kube-router: GoBGP gRPC Admin Port Exposed on Node Primary IP Without Authentication, Allowing Cluster-Wide BGP Route Injection

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary When the kube-router routing controller starts (--run-router), it binds the GoBGP gRPC management server to the node's primary IP (e.g., 192.168.1.10:50051) in addition to 127.0.0.1:50051. The default admin port is 50051 and the server is enabled by default with no TLS and no authentication. Any pod in the cluster can reach node IPs and therefore call the GoBGP gRPC API to inject arbitrary BGP routes, enumerate peer configurations, add unauthorized BGP neighbors, or withdraw legitimate routes. While kube-router's BGP export policy of ROUTEACTIONREJECT limits the attack surface to the local node's GoBGP RIB, an attacker can still impact local routing decisions. Details The gRPC server is started unconditionally when --run-router is active. In pkg/controllers/routing/networkroutescontroller.go, the startBgpServer(true) call at line 365 passes grpcServer=true, and the binding logic at lines 1057–1061 is: The default admin port is defined in pkg/options/options.go: No…

Published by the source

6 May 2026, 21:52 UTC

Last modified by the source

6 May 2026, 21:52 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v5mh-h5hx-7v92

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# Patch Next advisory brief: GHSA-v5mh-h5hx-7v92

Advisory: kube-router: GoBGP gRPC Admin Port Exposed on Node Primary IP Without Authentication, Allowing Cluster-Wide BGP Route Injection
IDs: GHSA-v5mh-h5hx-7v92
Record: https://patchnext.com/advisories/ghsa-v5mh-h5hx-7v92 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/cloudnativelabs/kube-router 2.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/cloudnativelabs/kube-router: affected <= 2.8.1; fixed in 2.9.0

## Suggested inspection (read-only)
- Go github.com/cloudnativelabs/kube-router: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/cloudnativelabs/kube-router.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-v5mh-h5hx-7v92 (GitHub-reviewed advisory GHSA-v5mh-h5hx-7v92 lists affected ranges: Go github.com/cloudnativelabs/kube-router >=0 <=2.8.1)

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