diff --git a/changelog/unreleased/fix-public-link-lock.md b/changelog/unreleased/fix-public-link-lock.md
new file mode 100644
index 00000000000..42a53432446
--- /dev/null
+++ b/changelog/unreleased/fix-public-link-lock.md
@@ -0,0 +1,6 @@
+Bugfix: Fix an error when lock/unlock a file
+
+We fixed a bug when anonymous user with viewer role in public link of a folder can lock/unlock a file inside it
+
+https://github.com/cs3org/reva/pull/4518  
+https://github.com/owncloud/ocis/issues/7785  
diff --git a/internal/grpc/services/storageprovider/storageprovider.go b/internal/grpc/services/storageprovider/storageprovider.go
index c125698c0b9..603315a460e 100644
--- a/internal/grpc/services/storageprovider/storageprovider.go
+++ b/internal/grpc/services/storageprovider/storageprovider.go
@@ -33,6 +33,7 @@ import (
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	typesv1beta1 "github.com/cs3org/go-cs3apis/cs3/types/v1beta1"
 	"github.com/cs3org/reva/v2/pkg/appctx"
+	"github.com/cs3org/reva/v2/pkg/conversions"
 	ctxpkg "github.com/cs3org/reva/v2/pkg/ctx"
 	"github.com/cs3org/reva/v2/pkg/errtypes"
 	"github.com/cs3org/reva/v2/pkg/events"
@@ -230,6 +231,11 @@ func (s *service) UnsetArbitraryMetadata(ctx context.Context, req *provider.Unse
 
 // SetLock puts a lock on the given reference
 func (s *service) SetLock(ctx context.Context, req *provider.SetLockRequest) (*provider.SetLockResponse, error) {
+	if !isPublicShareRoleEditor(ctx) {
+		return &provider.SetLockResponse{
+			Status: status.NewPermissionDenied(ctx, nil, "no permission to lock the share"),
+		}, nil
+	}
 	err := s.storage.SetLock(ctx, req.Ref, req.Lock)
 
 	return &provider.SetLockResponse{
@@ -249,6 +255,12 @@ func (s *service) GetLock(ctx context.Context, req *provider.GetLockRequest) (*p
 
 // RefreshLock refreshes an existing lock on the given reference
 func (s *service) RefreshLock(ctx context.Context, req *provider.RefreshLockRequest) (*provider.RefreshLockResponse, error) {
+	if !isPublicShareRoleEditor(ctx) {
+		return &provider.RefreshLockResponse{
+			Status: status.NewPermissionDenied(ctx, nil, "no permission to refresh the share lock"),
+		}, nil
+	}
+
 	err := s.storage.RefreshLock(ctx, req.Ref, req.Lock, req.ExistingLockId)
 
 	return &provider.RefreshLockResponse{
@@ -258,6 +270,12 @@ func (s *service) RefreshLock(ctx context.Context, req *provider.RefreshLockRequ
 
 // Unlock removes an existing lock from the given reference
 func (s *service) Unlock(ctx context.Context, req *provider.UnlockRequest) (*provider.UnlockResponse, error) {
+	if !isPublicShareRoleEditor(ctx) {
+		return &provider.UnlockResponse{
+			Status: status.NewPermissionDenied(ctx, nil, "no permission to unlock the share"),
+		}, nil
+	}
+
 	err := s.storage.Unlock(ctx, req.Ref, req.Lock)
 
 	return &provider.UnlockResponse{
@@ -1285,3 +1303,9 @@ func estreamFromConfig(c eventconfig) (events.Stream, error) {
 
 	return stream.NatsFromConfig("storageprovider", false, stream.NatsConfig(c))
 }
+
+func isPublicShareRoleEditor(ctx context.Context) bool {
+	u := ctxpkg.ContextMustGetUser(ctx)
+	psr := utils.ReadPlainFromOpaque(u.Opaque, "public-share-role")
+	return psr != "" && psr == conversions.RoleEditor
+}
diff --git a/internal/http/services/owncloud/ocdav/locks.go b/internal/http/services/owncloud/ocdav/locks.go
index 332b9d22760..e415e6a62d5 100644
--- a/internal/http/services/owncloud/ocdav/locks.go
+++ b/internal/http/services/owncloud/ocdav/locks.go
@@ -260,11 +260,15 @@ func (cls *cs3LS) Unlock(ctx context.Context, now time.Time, ref *provider.Refer
 		return err
 	}
 
-	switch res.Status.Code {
+	switch res.GetStatus().GetCode() {
 	case rpc.Code_CODE_OK:
 		return nil
 	case rpc.Code_CODE_FAILED_PRECONDITION:
 		return errtypes.Aborted("file is not locked")
+	case rpc.Code_CODE_LOCKED:
+		appctx.GetLogger(ctx).Error().Str("token", token).Interface("unlock", ref).
+			Msg("could not unlock " + res.GetStatus().GetMessage())
+		return errtypes.Locked("another token")
 	default:
 		return errtypes.NewErrtypeFromStatus(res.Status)
 	}
@@ -639,16 +643,19 @@ func (s *svc) unlockReference(ctx context.Context, _ http.ResponseWriter, r *htt
 		t = t[1 : len(t)-1]
 	}
 
-	switch err := s.LockSystem.Unlock(ctx, time.Now(), ref, t); err {
-	case nil:
-		return http.StatusNoContent, err
-	case errors.ErrForbidden:
-		return http.StatusForbidden, err
-	case errors.ErrLocked:
-		return http.StatusLocked, err
-	case errors.ErrNoSuchLock:
-		return http.StatusConflict, err
-	default:
-		return http.StatusInternalServerError, err
+	err := s.LockSystem.Unlock(ctx, time.Now(), ref, t)
+	if err == nil {
+		return http.StatusNoContent, nil
+	} else {
+		switch err.(type) {
+		case errtypes.Aborted, errtypes.Locked:
+			return http.StatusLocked, err
+		case errtypes.PermissionDenied:
+			return http.StatusForbidden, err
+		case errtypes.PreconditionFailed:
+			return http.StatusConflict, err
+		default:
+			return http.StatusInternalServerError, err
+		}
 	}
 }