SN-2026-024: GetObjectAttributes and Read-Only ZIP Archive Tag-Policy and GetObject Bypass

Wed, 11 Nov 2026 00:00:00 +0000

Status: Fixed on main (f746d0707, 296c9710b); scheduled for the next post-20261109 Server release
Identifier: SN-2026-024 (Security Advisory Ledger, #342)
Severity: High
Affected scope: SILO Server (RELEASE.2026-11-09T00-00-00Z and earlier) and inherited upstream MinIO releases since 2021-06-10 (ba5fb2365) and 2024-01-05 (9b8ba97f9)
Unaffected components: silo-console, mcli, silo-pkg, and kes

Standard GetObject and HeadObject handlers in SILO authenticate the caller first, read the addressed object version’s ObjectInfo, and then authorize s3:GetObject (or s3:GetObjectVersion) against objInfo.UserTags so IAM policies conditioned on s3:ExistingObjectTag/<key> take effect. Inherited from upstream MinIO, two read surfaces bypassed that post-metadata authorization step: GetObjectAttributes (GET /<bucket>/<key>?attributes) and the read-only .zip archive S3 extension (x-minio-extract: true on GET, HEAD, and ListObjectsV2). In addition, ListObjectsV2 archive member listing enumerated .zip contents using only bucket-level s3:ListBucket without checking s3:GetObject on the archive object itself, and reading an unindexed .zip archive persisted generated index metadata back onto the object during read verbs.

SN-2026-022: Active-Active Tagging Proxy Authentication and Remote Tag-Policy Bypass

Wed, 11 Nov 2026 00:00:00 +0000

Status: Fixed on main (14ecb222e, 67a90dfef, 293ab78b4); scheduled for the next post-20261109 Server release
Identifier: SN-2026-022 (Security Advisory Ledger, #337)
Severity: Critical
Affected scope: SILO Server (RELEASE.2026-11-09T00-00-00Z and earlier) and inherited upstream MinIO releases since 2024-01-12 (b2b26d9c9)
Unaffected components: silo-console, mcli, silo-pkg, and kes

When active-active bucket or site replication is enabled, an S3 object version may temporarily or permanently reside on a remote replication target while absent from the local cluster receiving a client request. To keep tagging operations transparent across peers, GetObjectTaggingHandler, PutObjectTaggingHandler, and DeleteObjectTaggingHandler (cmd/object-handlers.go) proxy requests for locally missing objects to active-active replication targets via proxyTaggingToRepTarget (cmd/bucket-replication.go), signing the outbound request with the server’s privileged replication credentials.

Tagging on SILO

SN-2026-024: GetObjectAttributes and Read-Only ZIP Archive Tag-Policy and GetObject Bypass

SN-2026-022: Active-Active Tagging Proxy Authentication and Remote Tag-Policy Bypass