diff --git a/keyserver/internal/cross_signing.go b/keyserver/internal/cross_signing.go
index 08bbfedb8..a6a2b7e78 100644
--- a/keyserver/internal/cross_signing.go
+++ b/keyserver/internal/cross_signing.go
@@ -552,6 +552,35 @@ func (a *KeyInternalAPI) QuerySignatures(ctx context.Context, req *api.QuerySign
 			}
 		}
 
+		for _, targetSection := range []map[string]gomatrixserverlib.CrossSigningKey{
+			res.MasterKeys,
+			res.SelfSigningKeys,
+			res.UserSigningKeys,
+		} {
+			for targetKeyID, section := range targetSection {
+				// Get own signatures only.
+				sigMap, err := a.DB.CrossSigningSigsForTarget(ctx, targetUserID, targetUserID, gomatrixserverlib.KeyID(targetKeyID))
+				if err != nil && err != sql.ErrNoRows {
+					res.Error = &api.KeyError{
+						Err: fmt.Sprintf("a.DB.CrossSigningSigsForTarget: %s", err),
+					}
+					return
+				}
+
+				for sourceUserID, forSourceUser := range sigMap {
+					for sourceKeyID, sourceSig := range forSourceUser {
+						if section.Signatures == nil {
+							section.Signatures = map[string]map[gomatrixserverlib.KeyID]gomatrixserverlib.Base64Bytes{}
+						}
+						if _, ok := res.Signatures[sourceUserID]; !ok {
+							section.Signatures[sourceUserID] = map[gomatrixserverlib.KeyID]gomatrixserverlib.Base64Bytes{}
+						}
+						section.Signatures[sourceUserID][sourceKeyID] = sourceSig
+					}
+				}
+			}
+		}
+
 		for _, targetKeyID := range forTargetUser {
 			// Get own signatures only.
 			sigMap, err := a.DB.CrossSigningSigsForTarget(ctx, targetUserID, targetUserID, targetKeyID)