Bug 2570953 (CVE-2026-115539)

Summary:	CVE-2026-115539 github.com/moby/swarmkit: SwarmKit: Privilege escalation via forwarded TLS identity overwrite
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in SwarmKit. The cluster Application Programming Interface (API) proxy can overwrite a forwarded client's Transport Layer Security (TLS) identity with an intermediary manager node's identity. During a cluster leader transition, an authenticated attacker possessing valid worker node credentials can route requests across intermediary manager nodes to acquire a manager certificate. This allows the attacker to achieve privilege escalation from a worker node to a cluster manager.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2026-11-10 20:32:52 UTC

SwarmKit's Cluster-API proxy can overwrite a forwarded client's TLS identity with an intermediary manager's identity. WithMetadataForwardTLSInfo replaces outgoing metadata with a copy of the incoming metadata, discarding the redirect guard's changes when built with grpc-go 1.39 or later. During a short window after a leader change, two proxy hops through managers with inconsistent views of the leader can allow an attacker possessing a valid worker node TLS certificate and private key to obtain a manager node certificate for the attacker's own key, escalating privileges from worker to manager. Applications built with an affected SwarmKit version and grpc-go 1.39 or later are impacted.