Skipper's routesrv-no-auth component: All routesrv API Endpoints Lack Authentication

Exploitation

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

CVSS

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

EPSS

• CVE-2026-54246: 0.34% estimated exploitation activity in the next 30 days; percentile 27.32 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description The routesrv component exposes the full cluster route topology (Ingress/RouteGroup configurations, backend URLs, filter chains, OAuth/OIDC callback paths) and cache-cluster topology (Redis/Valkey shard addresses) over plain HTTP with zero authentication. Any pod in the Kubernetes cluster can reach routesrv via its predictable DNS name and retrieve sensitive cluster-wide routing and cache infrastructure data. Vulnerable Code routesrv/routesrv.go:87-99,114-137 — all handler registrations on the main mux: routesrv/eskipbytes.go:134-196 — eskipBytes.ServeHTTP: routesrv/redishandler.go:28-41 — RedisHandler.ServeHTTP: routesrv/valkeyhandler.go:28-41 — ValkeyHandler.ServeHTTP: Attack Path 1. Initial Compromise: Attacker compromises any pod in the Kubernetes cluster (via application CVE, supply-chain attack, malicious container image, etc.) 2. Discovery: Attacker discovers routesrv via predictable Kubernetes DNS name: skipper-ingress-routesrv.kube-system.svc.cluster.local:9090…

Published by the source

17 Jul 2026, 21:46 UTC

Last modified by the source

17 Jul 2026, 21:46 UTC

Source last checked

26 Oct 2026, 15:25 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-5587-2x54-jj6h

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# Patch Next advisory brief: CVE-2026-54246

Advisory: Skipper's routesrv-no-auth component: All routesrv API Endpoints Lack Authentication
IDs: CVE-2026-54246, GHSA-5587-2x54-jj6h
Record: https://patchnext.com/advisories/cve-2026-54246 (revision 1, source checked 26 Oct 2026, 15:25 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/zalando/skipper 0.27.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/zalando/skipper: affected < 0.27.13; fixed in 0.27.13

## Suggested inspection (read-only)
- Go github.com/zalando/skipper: 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/zalando/skipper.
- 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-5587-2x54-jj6h (GitHub-reviewed advisory GHSA-5587-2x54-jj6h lists affected ranges: Go github.com/zalando/skipper >=0 <0.27.13)

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