Skipper routesrv-no-auth: All routesrv API Endpoints Lack Authentication

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-54246
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-14 20:16:45 UTC
Updated2026-09-16 13:42:48 UTC
DescriptionSkipper 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.

Risk And Classification

Primary CVSS: v3.1 5.7 MEDIUM from [email protected]

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

EPSS: 0.003380000 probability, percentile 0.270150000 (date 2026-09-15)

Problem Types: CWE-306 | CWE-306 CWE-306: Missing Authentication for Critical Function

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.7MEDIUMCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED5.7MEDIUMCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zalando Skipper affected < 0.27.13 Not specified

References

ReferenceSourceLinkTags
github.com/zalando/skipper/releases/tag/v0.27.13 [email protected] github.com
github.com/zalando/skipper/security/advisories/GHSA-5587-2x54-jj6h [email protected] github.com
github.com/zalando/skipper/commit/fb3d5f98ee749d9a1dfc5df2d51ac9b82fab92aa [email protected] github.com
github.com/zalando/skipper/pull/4056 [email protected] github.com
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