diff --git a/vendor.conf b/vendor.conf
index a88f05bd71..64d4fad331 100644
--- a/vendor.conf
+++ b/vendor.conf
@@ -33,7 +33,7 @@ github.com/imdario/mergo                            1afb36080aec31e0d1528973ebe6
 golang.org/x/sync                                   cd5d95a43a6e21273425c7ae415d3df9ea832eeb
 
 # buildkit
-github.com/moby/buildkit                            244e8cde639f71a05a1a2e0670bd88e0206ce55c # v0.8.3-3-g244e8cde
+github.com/moby/buildkit                            bc07b2b81b1c6a62d29981ac564b16a15ce2bfa7 # v0.8.3-4-gbc07b2b8
 github.com/tonistiigi/fsutil                        0834f99b7b85462efb69b4f571a4fa3ca7da5ac9
 github.com/tonistiigi/units                         6950e57a87eaf136bbe44ef2ec8e75b9e3569de2
 github.com/grpc-ecosystem/grpc-opentracing          8e809c8a86450a29b90dcc9efbf062d0fe6d9746
diff --git a/vendor/github.com/moby/buildkit/util/imageutil/config.go b/vendor/github.com/moby/buildkit/util/imageutil/config.go
index 0be587058a..a93c8ccd6b 100644
--- a/vendor/github.com/moby/buildkit/util/imageutil/config.go
+++ b/vendor/github.com/moby/buildkit/util/imageutil/config.go
@@ -183,19 +183,39 @@ func DetectManifestMediaType(ra content.ReaderAt) (string, error) {
 
 func DetectManifestBlobMediaType(dt []byte) (string, error) {
 	var mfst struct {
-		MediaType string          `json:"mediaType"`
+		MediaType *string         `json:"mediaType"`
 		Config    json.RawMessage `json:"config"`
+		Manifests json.RawMessage `json:"manifests"`
+		Layers    json.RawMessage `json:"layers"`
 	}
 
 	if err := json.Unmarshal(dt, &mfst); err != nil {
 		return "", err
 	}
 
-	if mfst.MediaType != "" {
-		return mfst.MediaType, nil
+	mt := images.MediaTypeDockerSchema2ManifestList
+
+	if mfst.Config != nil || mfst.Layers != nil {
+		mt = images.MediaTypeDockerSchema2Manifest
+
+		if mfst.Manifests != nil {
+			return "", errors.Errorf("invalid ambiguous manifest and manifest list")
+		}
 	}
-	if mfst.Config != nil {
-		return images.MediaTypeDockerSchema2Manifest, nil
+
+	if mfst.MediaType != nil {
+		switch *mfst.MediaType {
+		case images.MediaTypeDockerSchema2ManifestList, specs.MediaTypeImageIndex:
+			if mt != images.MediaTypeDockerSchema2ManifestList {
+				return "", errors.Errorf("mediaType in manifest does not match manifest contents")
+			}
+			mt = *mfst.MediaType
+		case images.MediaTypeDockerSchema2Manifest, specs.MediaTypeImageManifest:
+			if mt != images.MediaTypeDockerSchema2Manifest {
+				return "", errors.Errorf("mediaType in manifest does not match manifest contents")
+			}
+			mt = *mfst.MediaType
+		}
 	}
-	return images.MediaTypeDockerSchema2ManifestList, nil
+	return mt, nil
 }