# CVE-2026-54246

## Summary

- **CVE ID:** CVE-2026-54246
- **Severity:** MEDIUM
- **CVSS Score:** 5.7 (CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
- **CWE:** CWE-306
- **Published:** Sep 14, 2026
- **Last Modified:** Sep 15, 2026

## Description

Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.27.13, the routesrv component serves cluster-wide control-plane data without application-layer authentication through /routes, /routes/{zone}, /swarm/redis/shards, and /swarm/valkey/shards. The handlers registered in routesrv/routesrv.go, eskipBytes.ServeHTTP in routesrv/eskipbytes.go, RedisHandler.ServeHTTP in routesrv/redishandler.go, and ValkeyHandler.ServeHTTP in routesrv/valkeyhandler.go only restrict HTTP methods and do not authenticate callers. A compromised or otherwise attacker-controlled pod that can reach routesrv on the Kubernetes cluster network can bypass its namespace-scoped RBAC and read Ingress and RouteGroup backend URLs, filter-chain and OAuth or OIDC path details, and Redis or Valkey shard addresses across namespaces. NetworkPolicy can restrict reachability but does not remove the missing-authentication condition, and the established impact is confidentiality exposure rather than direct integrity or availability loss. This issue is fixed in version 0.27.13.

## Affected Products

- zalando — skipper (< 0.27.13)

## References

- [CNA](https://github.com/zalando/skipper/security/advisories/GHSA-5587-2x54-jj6h)
- [CNA](https://github.com/zalando/skipper/pull/4056)
- [CNA](https://github.com/zalando/skipper/commit/fb3d5f98ee749d9a1dfc5df2d51ac9b82fab92aa)
- [CNA](https://github.com/zalando/skipper/releases/tag/v0.27.13)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.34%
- **EPSS Percentile:** 27.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-19._