CVE-2026-34204: Replication Metadata Injection

Wed, 15 Apr 2026 00:00:00 +0000

Status: Released
First containing release: RELEASE.2026-04-17T00-00-00Z
GitHub issue: pgsty/minio#24

Ordinary PUT and COPY requests could smuggle X-Minio-Replication-* headers into internal X-Minio-Internal-* SSE metadata, creating objects whose replication state did not match the authorized path and could even make them unreadable. The final fix stopped accepting replication-only metadata by default, restored it only in a trusted flow authorized for ReplicateObjectAction, and sanitized CopyObject before any header consumer ran.

Threat model

An attacker needed only ordinary object-write permission, not internode credentials. The input came entirely from client-controlled X-Minio-Replication-* headers, but metadata extraction converted it into internal replication or SSE state.

Replication on SILO

CVE-2026-34204: Replication Metadata Injection

Threat model